I sometimes find it useful to think about acknowledgments for expenses incurred in terms of the more common situation of gifts of property.
In both cases, the non-profit organization provides an acknowledgment that describes what the donor provided, whether that is some item of property or services as a volunteer. The non-profit organization also documents what, if any, substantial benefits were provided to the volunteer in consideration of their property/service.
In both cases, the donor then takes that acknowledgment from the non-profit and adds their own documentation of the value of, in one case, the property they contributed, and, in the other case, the type and value of the expenses they incurred arising from providing that service.
It's also worth noting that the expenses are only deductible if they arise solely from providing the voluntary service, and are not also associated with, for example, vacation that might have also been occurred when the volunteer was traveling to provide the service. That is not anything that the non-profit organization is in a position to know, so it appropriately falls to the volunteer to identify which expenses arose entirely from their voluntary service, and then determine their value. Similarly, the organization is not in a position to know what the expenses were other than what the volunteer tells them, so it is quite properly left to the volunteer to substantiate the expenses themselves, without involving the ono-profit organization..
My US$0.02 worth; the usual disclaimers apply.
Good luck!
Alan
Alan S. Hejnal (he/him)
Data Quality Manager
