Well IvanK, had RAE chosen the lowest available speed and max lift coefficient values for the Spitfire and the highest available speed and max lift coefficient values for the 109, at the altitude which is most favorable for the 109, their results would have agreed with Crumpp's
Ironic mode off: Why waste time with obviously deeply biased stuff? Just google with keywords: Crumpp Spitfire calculation. You will get thousands of hits from the several sim forums over the past few years, I think he has produced enough text and calculations for several books.