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                                                                EXHIBIT 10.18


August 4, 1997


Mr. Steven J. Tonissen
196 Orchard Hills
Ann Arbor, MI 48104

RE:          Letter of Understanding


Dear Steve,

This letter ("Agreement") confirms the terms and conditions of your termination
from Comshare, Incorporated ("Comshare") under mutually agreed upon
circumstances.

The arrangement will be as follows:

1.  Your termination from Comshare, Incorporated will be effective on 
    August 25, 1997 ("Termination Date").
2.  Comshare agrees to pay you salary continuation pay commencing from your
    "Termination Date" until February 25, 1998 ("Salary Continuation Period").
    If you secure other employment prior to this date, Comshare agrees to pay
    the difference, less appropriate federal and state withholdings and
    deductions, between the amount of salary continuation pay already paid to
    you and the total amount that would have been paid through February 25,
    1998. You will be paid $7,692.31 bi-weekly during the Salary Continuation
    Period, less appropriate federal and state withholdings and deductions, on
    Comshare's regular, scheduled pay dates. Your group health, dental, vision
    and life coverage, including elected dependent coverage, which are
    currently in effect shall continue for you and any of your covered
    dependents until February 25, 1998, or until you are eligible for insurance
    from other employment, whichever occurs first, provided that Comshare shall
    have the right to change such coverage to the extent that Comshare is
    generally changing coverage for its employees.  You shall continue to make
    required contributions, via payroll deductions, at the then current rate
    for similarly situated Comshare employees.  Long term disability coverage
    ceases on your Termination Date.  As discussed, this agreement does allow
    you to work as a consultant in businesses other than those listed on the
    August 6, 1997, addendum to the Comshare At Will Employee Agreement.
3.  You are eligible to participate in an executive outplacement program.  As
    agreed, the costs of the program, $12,500.00, less appropriate federal and
    state withholdings and deductions, will be paid directly to you for use at
    your discretion.
4.  Your bi-weekly car allowance of $436.15 will be continued through 
    August 31, 1997.
5.  Comshare shall make available to you and your qualified dependents the 
    election of coverage under the Consolidated Omnibus Budget Reconciliation
    Act of 1985 ("COBRA") at the time required by COBRA. 
6.  You will not accrue vacation benefits during the Salary Continuation 
    Period. Our records indicate that you have ten (10) vacation days. 
    Vacation will be paid to you less appropriate federal and state
    withholdings and deductions, within two (2) weeks of August 25, 1997.
        

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7.  You will not be eligible to continue your participation in the Profit 
    Sharing Plan, including the 401K option, throughout the Salary Continuation
    Period. You will be apprised of your options, with respect to such plans,
    under separate cover.  Your participation in the Employee Stock Purchase
    Plan will end immediately and a refund check for contributions deducted
    from July 1, 1997, will be refunded to you.
8.  Except for publicly held information, all information to which you had 
    access during your employment with Comshare or as a result of your dealings
    with Comshare and/or any clients, customers, suppliers or business partners
    shall be kept confidential and shall not be disclosed to any third party. 
    This information includes, without limitation, a) computer programs,
    technical specifications, software programming techniques, methodologies,
    ideas concepts, or interfaces; b) information which relates to Comshare's
    proprietary software, prototypes, or plans; c) business, financial,
    marketing or sales plans and data; d) customer lists and information; and
    e) other information.  Your confidentiality obligations under this
    paragraph are in addition to those set forth in your Comshare Employment
    Agreement.
9.  You shall not discuss any of the terms of this Agreement with any third 
    party including, but not limited to, other Comshare employees.  In
    addition, You shall not comment on the business affairs, policies or the
    like of Comshare without the specific written approval of Comshare.
    NOTWITHSTANDING THE FOREGOING, YOU MAY BE ENCOURAGED TO PROVIDE A COPY OF
    THIS AGREEMENT TO LEGAL COUNSEL AND OTHER OUTSIDE ADVISORS OF YOUR CHOICE
    TO OBTAIN SUCH COUNSEL AND ADVICE AS YOU DEEM APPROPRIATE.               
10. You have stated that you have returned to Comshare all property of Comshare
    in your possession and/or subject to your control, including, but not
    limited to, any and all credit cards, files memoranda, correspondence,
    customer lists, proposals, software or the like, and all copies of such
    items on whatever media they appear.  If you uncover additional company
    property please return it to the company.  This provision excludes your
    Comshare issued personal computer that you may retain for your use, as
    agreed, until September 30, 1997.
11. It is understood that this Agreement and your Comshare Employee Agreement,
    dated May 27, 1995, constitute the entire understanding of the parties with
    respect to your employment at Comshare and that this Agreement and your
    Comshare Employee Agreement supersede all other understandings, proposals,
    samples, models, agreements, representations, or conditions, written or
    oral, regarding its subject matter.  In the event of a conflict between the
    terms of this Agreement and your Comshare Employee Agreement, the terms of
    this Agreement shall take precedence.
12. You acknowledge and agree that you will not be eligible for and are not
    entitled to severance pay or other considerations at the end of the Salary
    Continuation Period.
13. In exchange for the good and valuable consideration detailed in this 
    Agreement and effective as of the date you sign this Agreement and for all
    acts prior to such date, you hereby release, waive and discharge any and
    all manner of action, causes of action, claims, rights, charges, suits,
    damages, debts, demands, obligations, attorney's fees, and any and all
    other liabilities or claims of whatever nature, whether in law or in
    equity, known or unknown, including, but not limited to any claim or claims
    of damages or other relief for tort, breach of contract, personal injury,
    negligence, age discrimination under the Age Discrimination in Employment
    Act of 1967 as amended, employment discrimination prohibited by other
    federal, state or local laws 
        


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    including discrimination as to sex, race, national origin, marital status,
    age, disability, height, weight or religion, and any other claims of
    unlawful employment practices, and any other similar and dissimilar claims,
    which you have claimed or may claim or could claim against Comshare,
    Incorporated, its direct and indirect subsidiaries or their respective
    directors, officers, employees, successors, or assigns, as a result of
    employment at and the separation from employment with Comshare or
    otherwise.
14. You acknowledge that you have read this Agreement and that you understand 
    all of its terms and execute it voluntarily with full knowledge of its
    significance and consequences thereof.  Further, you acknowledge that you
    have had twenty-one (21) days to consider the terms and conditions of this
    Agreement. In addition, you shall have a seven day period following your
    execution of this Agreement, during which you may revoke the Agreement by
    providing Comshare with written notice to that effect. (Any notice should
    be addressed to the attention of the undersigned.)  Finally, you hereby
    acknowledge that you have had an adequate opportunity to review and
    consider the terms of this Agreement, and have discussed this Agreement
    with legal counsel of your choice.  You agree that you grant a full and
    final release as set forth herein.
15. The Agreement shall be governed by and construed according to the laws of 
    the State of Michigan.  The Agreement shall be binding upon you and your 
    heirs, administrator, representatives, executors, and assigns.
16. Sections 6, 7, 8, 10, 11, 12, 14 shall survive the end of the Salary
    Continuation Period.

If the above is acceptable, please sign this Agreement and return it to me by
August 22, 1998.  If I am not in receipt of a copy of this Agreement, executed
by you on or before that date, this offer shall be void.

Sincerely,
Comshare, Incorporated


/s/ Carol A. Peterson
--------------------------------
Carol A. Peterson
Sr. Director, Human Resources


The above terms and conditions are agreed to and accepted:

/s/ Steven J. Tonissen
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Steven J. Tonissen

August 4, 1997
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Date






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