Well on the eastern front the LW really had success, and LW veterans have often said that it was tougher in the air on the western front. (Apart from the side that the russians often executed POW's). So, this sticks out even better if 2/3 of the LW are on the eastern side while their losses are more on the western side.
The LW had 'real success' in the West. Not only against bombers but fighters as well.
30 LW pilots 'out scored' the top Ami pilot, this only considering their scores against Ami aircraft.
Eder scored 56 kills against the Amis alone; twice the number of the top Ami.
Not to mention the number of 100 kill Experten scored against Western Allied aircraft. The top LW Spitfire killer, Priller, shot down 68 Spits...
What made the West difficult was the objectives the LW was tasked with, that is stopping allied bombers. In the East the VVS was used in conjunction with ground forces and its objectives mostly were ground targets. This gave the LW the advantage. In the West with the majority of the LW were going after bombers this gave the Allied escort fighters the initiative etc...
Not to mention the steady build up or pilots and equipment as the war progressed:
On 6 June 1944, the Allies had a total of 13,000 aircraft ready to support the Normandy invasion. The Luftwaffe had 1,300 aircraft at its peak (reached on 10 June) in France.
Many LW pilots say the VVS pilots, especially later in the war, were better 'fighters'.
I often found myself alone pursued by eight or ten Mustangs, and was able to survive only by mobilising all my flight skills, twisting and turning around small woods and church towers in low-level flight. I was aided by the lacking skills on behalf of the American pilots, since each one of them wanted to shoot me down, and thus they blocked each other.
Major Hans-Ekkehard Bob Kommodore JG 3
Despite all the nonsense some of the top scorers in the East scored the majority of their kills post '43...
Fighter Combat in the East and in the West - A Comparison