Late fees are only due per the terms of a contract. The contract speaks of a (singular) late fee that becomes due if rent is paid after the fifth of the month, not a late fee that is charged each day rent is late. Its not so much a matter of "what kind of day the judge is having", and much more a matter of whether the judge has an IQ above room temperature. I make no promise about the IQ of any given judge, but a court
should decide this one in the OP's favor.
(As an aside, unless rent is exceptionally high, Washington is unlikely to approve a $75/day late fee. See
RCW 19.150.150,
Buchanan v. Kettner, 97 Wn. App. 370, 984 P.2d 1047 (1999).
Buchanan also provides an example of what a late fee clause that includes a daily late fee should look like.)