wells fargo telling me that one day is the same as 30 days late

[Rachael Collins]

I am working on a  refi for my primary residence. It's a rural property (20acres) and we bought it with private money. In providing mortgage payment verification to Wells Fargo they are telling me that checks dated one day after the due date is considered the same as 30 days late. The payment is due on the 26th,  so I wondered if the few checks dated the first or second of the next month made them think it was thirty days based on a due date of the first of the previous month.  However, as indicated above they said one day is the same as 30 days late.  Is this normal, or legal? I know loan requirements are strict, but this seems excessive.  Thanks-