Are you sure it is not 7-8 kPa per 1/8 turn? If that is the case everything makes sense.
YS 185 nitro: 1.1-1.2 bar @ idle.
For YS 185 Zero, YS suggest leaning the pump på 1/4-1/2 turn:
1/4 turn gives 14-16 kPa ( 0.14 – 0.16 bar ) pressure reduction
1/2 turn gives 28-32 kPa (0.28 – 0.32 bar)
YS 185 Zero: 0.78 bar (1.1 -0.32) – 1.06 (1.2-0.14) bar
I am at 0.8, at the lower end of the range.
Would be interesting to hear if anybody else has any experience, I guess there will be some variation.