Earlier quoted context omitted.
For the SNAP law, could they just round down SNAP purchases in the same way to be compliant?
The SNAP equal treatment rule requirement works in both directions: Prices cannot be higher or lower for SNAP recipients. As a retailer, there is an option to request a waiver, though.
The law did not account for every possible situation. Removal of the penny from national currency is clear a situation where minor variations on otherwise normal transactions would not be in violation of the intent of the law.
It'd be like TSA griping that your 100ml bottle of mouthwash was overfilled by .1ml because of slight variations in the filling process. Nobody cares.