I like the plan in general. I see what you're doing.
That said, if I was going for powerlifting totals, I'd up those percentages somewhere. The most you're doing is 85% for 8 sets of 3 if I'm reading that right. That's great volume, but you will need some sets above 90% somewhere along the line to keep getting stronger.
I would hit a max single or two on heavy days, then drop back down to do the 8x 3. I would also seriously consider hitting a single around 90% (no higher) on medium days, then dropping back down for the reps that day too.
Just a thought. When you're starting out lots of reps is a good thing, but you need a little intensity too.
Post a log and see what happens. Good luck!
I am Anton Zdravko Martin!
Best meet lifts: Sq 150 Kg (330 lb), Bench 120 Kg (264), DL 160 (352) @89 Kg (197)
Best gym lifts: Sq 375, Bench 280 (pause), DL 385 @205 or less
Goals beyond my wildest dreams, 600 Kg raw total, 200/160/240
Hack away at anything which isn't essential. Do what you love, and do it often. Fazc.
Everything competes for recovery so more assistance is not always the best idea. miked96