Dave Honke suggested to measure the shaft again after its FLO was found.

CPM @ FLO : 391.07 ± 1.33
CPM @ FLOW +90° : 389,61 ± 0.65
CPM @ FLOW +180° : 390,92 ± 0.80
CPM @ FLOW +270° : 390,11 ± 0.99

As you can see below the cpm is still increasing.