IL-2 1944 speeds

[FeuerFliegen]

The IL-2 1944 speeds are listed as follows:

 

Maximum true air speed at sea level, engine mode - Boosted: 412 km/h
Maximum true air speed at sea level, engine mode - Nominal: 391 km/h
Maximum true air speed at 1200 m, engine mode - Nominal: 386 km/h

 

 

What sense does it make that it's slower at 1200m?  It still produces full boost at that altitude.  the 1943 model is faster at 1200m than it is at sea level, and the planes are almost the same other than the wings.  Is this just a typo?

[jokash]

Its optimized for low altitude?

[Kubert]

Fear of low caliber AA fire makes IL-2 fly faster at sea level.