20 more mins is a 3x floc multiplier. That's a tad high for a parm. I do 2x max, and that's with winter milk. If the set seems to be progressing okay, I'd cut at 2x into 1/2", then let the curd heal for 5-15 mins (depends on how the curd looks, with winter milk it's closer to 15), then finish cutting to 1/8" and start bringing up the temp.