It is contractual. There is no need to spend any $$. It is $25 period, dot.
When I enter it into the OOPE, simply put NOCAT as the vendor and then TYS (for this example)
This is Different than missed catering or the Company meal. In theory, supposed to use the Company Credit card for these expenses and you are reimbursed up to $25 for the inconvenience. I've bought many a ramper a snack\dinner getting the cost up to my reimbursable amount.