As for PSC/BBSE, it seems to come down to specific kit compatibility. I'm not surprised Zen's kit is working so well; Hicookie has one that works perfectly too. Pt1t had one that was doing 1270+ 8-11-7 with 1.72V at the GBT France office too (later it no longer worked). When I tested the BBSE in GBT France, couldn't get it to run anywhere near 1250 8-12, but when swapping out for the 2nd-gen Flare kit those speeds were easy.
Some kits just work and others really don't. It has very little to do with IMC quality or 'effort'.