Schedule M-1 (Form 1065): Reconciliation of Income (Loss) per Books With Income (Loss) per Return. Labeled 'Schedule M-1' within a Form 1065 filing. Reconciles book income to tax return income; shows items treated differently for book vs. tax purposes. Typically this schedule is part of the standard Form 1065 return packet and should be included in the Form 1065 subdocument. Only classify it separately when it is clearly a standalone schedule packet outside the core Form 1065 page sequence. Schedule M-1 pages within a Form 8865 (foreign partnership) or Form 1120-S should remain part of that parent form's subdocument.