There is evidently a Russian language version of PTTP that includes the 5/3/2 rep scheme. IIRC it was suggested to Pavel by Jack Reape, mainly for simplicity (less calculation and changing plates).
Personally, I prefer the 100%/90% version and the 4 steps forward/3 steps back wave cycle. I find it a great psychological boost when I use a weight for a back off set that was a top set earlier in a cycle. When the weights get heavy, I also find the 90% back off set mentally and physically easier, and easier to recover from, and it better allows me to really concentrate on specific form issues.
I like the 4/3 wave cycle (usually with bigger jumps between sessions and smaller jumps from the start of one wave to the start of the next) because it creates a nice rhythm of easier, medium, and more challenging sessions throughout the cycle. There aren't a bunch of easy sessions at the beginning or a death march of tough sessions at the end.