[Crumpp]

I highlighted the important bit.

I did the same for you!!

Unfortunately, you don't have any experience operating a variable pitch propeller to know how it works in the air.

Here is how to get extra performance from the Bf-109....

Increase rpm to....

To increase the performance of the Me 109 an increase in the revs for a short time at heights over 5.5 km. will be in future be
permissable. For the DB 601 A engine the normal maximum revs are 2400.
Above full pressure height they may be for a short time be increased
from 2400 to 2600...

And maintain it by:

Ulrich Steinhilper, in his auto-biography (chapter 16) , talks about managing the prop-pitch on the early (E3 and E4 variant) 109s during the Battle of Britain. He states that, in order to achieve max climb rate and airspeed (particularly at higher altitudes) one had to constantly increase and decrease the propeller pitch. Increasing the pitch would engage the supercharger, which would be run for a short period (i.e. a second or less?) to force more air into the cylinders, then the pitch would be dropped back down again to disengage the supercharger and convert the power gained into airspeed, and allowing the engine/ supercharger to rest.

All done to maintain 2600 rpm!!!

...the excess revs can only be obtained by
means of the thumb switch after switching off the automatic device.
In doing this the danger of an additional impermissable increase in
the revs must be watched.

Given that we know how a variable pitch propeller is operated and the physics of how it transfers power to the air we know this quote:

we constantly changed propeller pitch and RPM

Is a general statement without context of time line for rpm.

Not a stumbling block though as I said, we know the physics!!

Since propellers are optimal at a specific speed and rpm....

We know what the RLM meant in the their instructions and what Ulrich Steinhilper is telling us both fit together without contradiction!!