The issue of whether expense reimbursements should be included as “wages” when computing the regular rate for overtime has been around for many years. Sometimes, an employer will seek to “disguise” wages as expenses in order to avoid overtime. Sometimes, expense reimbursement is just that. These principles are possibly to be explored by the US

As a general rule, employee expense reimbursements are not includible in the regular rate for purposes of overtime computation.  When the reimbursements, however, are unreasonable or out of whack (i.e. too high) as regards the particular expense, then the USDOL takes the position that the reimbursements are really a backdoor way of paying the employee