My track wheels have SC2s that I use for DE they have about 20 sessions on them and the fronts still have good tread but rears need replacement. Do I need to do the fronts as well due to heat cycles or?

I’m a solid intermediate level driver.

here’s a pic for reference also the rears have been flipped once.

 

I get Cup 2 from Tire Rack and have them do the heat cycling for me to prep them. I have had no issues when I replace fronts or rears on different cycles. On my M2 I go through fronts first due to lack of negative camber so I get almost 3x the life from my rears versus fronts.