Which build are you running? 4.10 or the new one? 4.26?

Normally for flat spins I do go into a blender - straight down, no power. Full left aileron for 2 rolls then full right rudder, full down elevator, full left aileron. Then I slowly add power up about 3-4 clicks (on the stock yak) and come out of the aileron applying just a hair of right aileron.

Too much power it flops out. Not enough it will just kind of hang there then stall out.

Too much aileron it will go into a spin or just flop out.