You might start by reviewing the partnership agreement to ascertain that a partner may incur such expenses on behalf of the partnership, if applicable, as UPE or otherwise.  You might review the invoices to determine if such expenses were incurred in the partnership's name, or at least with respect to partnership authorized business.  If not, an accountable plan may be irrelevant.  I suspect the accountable plan rules focus on payments actually made to a partner (for actual expenses incurred for partnership business) but would need to look.  Are the ownership percentages changing with every hypothetical distribution and recontribution?