I would advise sending payments only to the extent that that debtor is unable to stay current.  Any payment should always includes the name of the debtor as well as the case number to insure proper credit.You raise an interesting question as to whether accelerated payments would create suspicion of an increased abiltiy on the part of the debtor to make the payments.  That all depends upon the accounting methods utilized by the Chapt. 13 trustee practicing in the district.  In my experience, one trustee might flag it, the other wouldn't care as long as the payments were made on a timely basis.  Additionally, one ought to be familiar with the specific terms of the debtor's chap. 13 plan.  Is it a percentage plan ofr a pot plan.  It may make a difference in the completion of the plan and the expected payments to creditors.