PRESSURE C     [bv force + press]     P.mv - P.bv = bv force
P.mv is the pressure variable in the bv force.  A stiffer bv stack will create higher P.mv, resulting in higher bv forces.  [see graph below] 'bv force' comes from  P.mv - P.bv. --->  P.bv is dependant on the icspr, and does not fluctuate with valving changes, but will increase slightly on the dyno as the temperatures increase. The press increases due to thermal expansion of the oil (there is no gas to expand with an icspr).