ADVICE NEEDED ASAPPP

A new fam that I have never babysat for wanted me to come for 4 hours but is now saying 2 hours. That’s honestly not worth the time or the headache of meeting a new family. Would it be weird to tell the family that I usually have a 4 hour minimum for new families? Obviously if I was with these people for a while I could do 2 hours if they really needed

Edit: Thank you so much to everyone for your input!