Ok to wait 74 hours between coats?
I'd like to mention though that you don't want to wait longer than say 5 days between coats. Latexes usually cure in about seven days, and you want the coats to cure together to provide one protective film. Most manufacturers say be sure to recoat before 7 days. Same would go for oil, but they have a much longer cure time usually around 30 days.
This is for finish coats. Although you wouldn't want to leave a primer sitting much longer either. You won't hurt anything waiting just a few days.