Spit IIa is now so much more inferior to the 109

The 109 was reputed to have the superiour climb than the spit so I do not see anything wrong with this.

I do not know the tendency of speed but there might simply be no general "plane X was faster than plane Y" but rather "between alt 1 and alt 2 plane x was faster than plane y and between alt 2 and alt 3 plane y was faster than plane x"

If you loose a combat try to analyse your mistakes first. You may become a good pilot in the end and perhaps you won't need to put the blame on the fm anymore.