There is a limit to how long you can focus on a single task for longer periods of time before you need to rest up properly to recharge your batteries. Everything beyond that will lower your productivity, up to a point where you will end up negative due to the mistakes being made. If you are lightweight on useless processes and stuff, a 30 hour week would be way more optimal for a lot of people. Crunch time should be very short and if stuff cannot be "crunched" in a single week it is useless to continue on like that, because everyone involved will be like 50% as effective as someone just working 30h per week (who can focus on the actual work).