It would be nice to have a tutorial as well as more documentation about the science of what the app is doing for you, like the small "Learn more" link under the timer menu. 

If you design your own custom workouts, will the app apply the same machine learning to those like it does with the prebuilt programs?

It's really a matter of old habits and availability of weights in the gym.  Hence, I have found it more efficient to go with the flow and do my upper body workout days prior to the lower body workout days.  Understand the "rest" between workouts theory that makes lower body done before upper - so willing to modify.  But it is easier in this gym to do it in reverse order.

At some point during the progression, there should be a "Are you ready for a 1 rep max test?"  Then it's a 5/3/1 workout to see if what the app thinks you can do, you can do.  If not, that's fine, adjust as necessary.  But strength is an important concept that should be tested time to time.  Always the option to skip an exercise if you don't feel like doing a 1 rep max workout every so often.  Goes more with a strength training phase of the program vs always in the 6-12 range.  At some point, it's fun to do the 4-6 range to just bang out heavy weight.

From a UI perspective when I'm done with my routine do I SAVE it or do I FINISH it?  The button at the bottom after I'm done with my workout for the session should be Finish Workout vs Save.  Saving is for data in progress (I saved my Excel document).  Finish is for the end (I finished my workout today or I saved my workout today?).  Semantics sure.. but it's much more intuitive to Finish a workout and have it saved into the history.

Today while working out, I was doing 355lbs on bench press for 4 sets of 4 reps. On my 3rd set I struggled hard on my last rep. Coming into my 4th set I decided to drop to 335, and I was able to push out all 4.  I forgot to change 355 to 335 on set 4, and hit finish exercise.  It showed me a 6% increase, and then I remembered I hadn't changed the last set.  I changed set 4 to 335, hit finish exercise, and it still showed a 6% increase.  Not sure how exactly the app makes this determination, but I'm assuming it wouldn't be the same increase in both scenarios?  

Exercise list >

bench press >

Loading >

Lock screen >

Unlock screen >

The app crashes

I think we should never turn off the screen when it loads or do calculations ... I do not know if it is because of my pattern lock to unlock my phone when I turn it on again ...?

But it must do that to other guys too

If I feel my initial estimation of a 6RM (i.e., not actually tested for some reason) is low and want to test/6RM this exercise at a random point, what's the best way to enter this new 6RM in the exercise I am already doing? Switching off and on this exercise doesn't ask again for a 6RM.

A quick solution, I guess, would be to rename this exercise and enter it in your workout (e.g., Squat, Deep instead of Squat), but of course, long term, you wouldn't have the whole progression of an exercise...

Include an option for increasing the font-size. I don't wear my reading glasses at the gym and it is very hard to see the text! There is a lot of wasted screen when performing an exercise!