When the G10 and K4 entered the skys in 10\44 it was against allied fighters updated with 150 Grade. Not into a pre D-Day sky of 125&130 Grade fighters. Allied command being aware that Germany still had more powerful fighters to introduce over the continent pre D-Day, the upgrade to 150 Grade 11 months before the war ends and 3 months before the emergence of the G10 and K4 makes it an acceptable part of the arms race this game purports to represent.
The K4 met allied fighters burning 150 Grade which made the technological differences far narrower than in our LWMA where the K4 is competing against the same generation of aircraft burning 125 or 130 Grade. Especialy with the way we conduct flight operations in the LWMA most of the time below 15k where it's obvious the 150 Grade turned the K4 into an equal and not an unperked WEP monster.
So why do we have an unperked 10\44 WEP monster flying against it's 1944 Allied rivals down graded in performance by pre 7\44 125, 130 AvGas? The K4 performance in the LWMA especialy on the deck versus the spitXIV on 125 or 130 show cases why the Allies began the move to 150 Grade in 7\44 months before the introduction of the K4. 
Or do we need a Post D-Day "Really Late  War" arena with only 109G6-14\K4, Fw190A8\D9, Ta152, 262, 163 versus Merlin66 spit, spit14, tempest, P51D, 38J\L, P47D-40\M burning 150 AvGas? And maybe a Meteor for grins and giggels.
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So what were the Allies over the ETO doing with all of this 150 Grade fuel for the last 11 months of the war, starting before the introduction of the K4?Sea Level---------------------130 Grade--- 150 Grade  
SpitfireIX--------------------  335 mph----- 358 mph    +25 lb  
SpitfireXIV------------------  359 mph------ 366 mph    +21 lb  
Tempest V------------------- 372 mph------ 386 mph    +11 lb  
Mustang III (V-1650-3)----- 360 mph------ 390 mph    +25 lb  
Sea Level------------B4 Grade
BF109-K4 -----------368mph
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Consumption of 150 Grade Fuel - Barrels
        UK consumption   North West Europe
    June 1944   184,000 (25,205 tons)
    July 1944   283,000 (38,767 tons)
    August 1944   218,000 (29,863 tons)
    September 1944   169,000 (23,150 tons)
    October 1944   183,000 (25,068 tons)
    November 1944   140,000 (19,178 tons)
    December 1944   193,000 (26,438 tons)
    January 1945   138,000 (18,904 tons)   of which 15,000 (2,054 tons)
    February 1945   148,000 (20,273 tons)   of which 17,000 (2,328 tons
    March 1945   201,000 (27,534 tons)   of which 52,000 (7,123 tons)
    April 1945   208,000 (28,493 tons)   of which 89,000 (12,191 tons)
    May 1945   49,000 (6,712 tons)   of which 32,000 (4,383 tons)
    UK = 8th AAF and ADGB. Northwest Europe = 2nd TAF.
    Other figures.
    August 1944   USAAF 182,000 (24,931 tons)   RAF 49,000 (6712 tons)
    October 1944 estimated   USAAF 225,000   RAF 45,000
    December 1944 issues   USAAF 133,000   RAF 0
    December 1944 exports   USAAF 8,000   RAF 88,000
    December 1944 issues on continent.   USAAF 0   RAF 13,000
    7.3 Barrels = 1 ton.
    Data from POWE 33/990 33/991 33/992 33/985 
http://www.wwiiaircraftperformance.org/150grade/Consumption_150_Grade_fuel_Barrels.html