Spit IIa is now so much more inferior to the 109

[Crumpp]

I checked the June 1941 edition. It doesn't contain any general statement that aircraft or engine limitations are allowed to be exceeded. It does however explicitly state that the over-ride for the boost control of "an engine normally rated for [...] 87 otane fuel" "may be used only if 100 octane fuel is in the tanks."

Let's see the whole publication because they do not match at all. Either the warning about 100 Octane is a technical update added at a later time or it is not from the same document.

The 1937 Training Manual makes no such distinction about 100 Octane fuel.