Thanks!😀
Warning switch is in the combination valve. This valve only has a proportioning valve at the out port for rear brake line. No metering valve for the fronts at it s a disc-disc design. So other then housing a warning switch and a prop valve to the rear to awoid rear locking when panic braking it only functions as a distributor block.

I does not build pressure or create a drag.
I agree about removing the combination valve.

I jus wonder if the rear calipers can play a part here. They are adjstable and rests with a gap between rotor an pads. I never ratceted the parking brake before bleeding. Wonder if there is air trapped in the calipers making the pressure differential valve trip during hard braking.

As stated brakes feel super nice under light braking. No extra effort needed to slow down calm, but there is just not more stopping power to get.