At the moment, the app has me doing 4 work sets, two warm up sets and a longer lighter set at the end for most (but not all) exercises. The rest times between sets on their own add up to more than an hour, so it really is impossible to complete in 60 minutes.

I could do shorter rest periods than the app suggests, but I assume that the rest periods suggested by the app are the optimal periods and the whole point of having the app is that it's meant to calculate all that for us so that we can just follow the instructions and see growth.

Sorry, I meant to say it always gives an estimate of 60 minutes.