Filter adjustment on Rolleiflex F cameras

I don't understand the filter exposure adjustment on the side of the Rolleiflex F cameras. Is it filter factor or stops?

My understanding from the manual is that the filter exposure adjustment wheel on the ASA/DIN adjustment knob is marked in filter factors. So, turning it to 1.5 for a medium yellow filter would increase the exposure by 2/3 of stop. However, on my camera (3.5F version 3) it seems to adjust in stops, not filter factors. Turning it to 1.5 means that I am exposing 100 ISO film at about 38 ISO, not 64. Can anyone confirm?

Thank you.

jason

This are stops.

Thank you. The manuals were unclear about this. It does seem odd, as Rollei filters are marked by filter adjustments, while they mark it on the camera by stops.