Very interesting stats, Michael - thank you.
So your original estimate that you would be at about 25% without the pause button needs some fine-tuning - because you were at about 50%, even without the pause button, if you count not finishing in time/errors/near misses - which I would, always, count.
That's actually a perfectly normal rate of progress!
Which means the issue here is how you feel about not remembering the new stuff.
At the moment, you're clearly responding very emotionally - 'getting ridiculous', 'failed miserably' - based largely on the perception that you've either 'retained' or 'not retained' the new material. But retained/not retained isn't a binary state - each time you're exposed to any given piece, it moves a step towards being an accessible long term memory.
Now, if you can suspend your disbelief so that you go through the sessions without blaming yourself so much for the ones you don't remember (try blaming me instead!) - you'll find it easier to run the experiment of going through to 10 without any repetitions - and then we'll see what stats you produce when you revisit 3. That's what will show you, one way or another, whether the approach is working for you.
So please don't revisit 3 until you've had one go each, ideally with stats in here, at 4 to 10...