I would like one question,why is not included in this part of the E4 Messer?

[fruitbat]

Hooton in Eagle in Flames gives the percentage losses of 109s by subtype:

July
E1 - 44%
E3 - 30%
E4 - 20%

August
E1 - 40%
E3 - 8%
E4 - 52%

September
E1 - 38%
E3 - 1%
E4 - 61%

October
E1 - 36%
E3 - 2%
E4 - 62%

and from Kurfust, over at ubi a while ago,

"I have some actual numbers. On 31 August 1940, fighter units (excluding JG 77) reported 375 E-1s, 125 E-3s, 339 E-4s and 32 E-7s on strength, indicating that most of the E-3s had been already converted to E-4 standard. JG 77 had around 100-125 aircraft with it, but for the rest of the units, its 75% cannon E-3/4/7, the rest are all MG E-1s. The E-1 and E-3 were produced parallel and in about equal numbers from the end of 1938, but by mid-1940, the production of the E-1 stopped, replaced by the E-4 and then the E-7."

and

In Ulrich Steinhilper's book 'Spitfire on My Tail', he relates quite clearly that they, JG52 didn't get there first cannon armed 109's until mid september , and then only 2, which were hand me downs from another unit. Rest of the unit bar these 2 planes was still in E1's.

Its pretty clear that the E1 and E4 were the most common variants by far and that around SEPTEMBER sometime, the E4 became more prevalent than the E1, which had been the most common type until then, but even it October a third of the losses were still E1's.

which makes the E3 choice mystifying to me.