That is interesting Ray, It sounds like the odd readings we got with the Pavesi.
A few things that may be influencing the readings. My rotax turned over at starter rpms with a full charged battery, should make note of that rpm. Be sure full throttle is applied during tests. Squish measurement should be recorded with the test along with air density.
I haven’t tested my new build yet. I have a starter bolt mounted inside my rear axle so that I can us an electric starter on it. I will get that reading then compare it to a reading with a few pulls of the strap around the tire. But what gear should be used when starting and testing? I use 2nd gear usually yet right now I have 14 X 28 gearing on it for ice racing which is regulating the cranking speed.