Carpet bombing GVs with heavys has been around for the whole time I have played.
As to the attack score, well heavy bombers don't have attack scores and if you do use a Lanc, B17 etc to bomb GV's you hurt your bomber score, as your dropping 3 bombs to hit one target.
Exactly.
If anything, carpet bombing Gvs in heavies wrecks your bomber score, as you gain nothing in actual score from it -kills don't count in score and your hit % and damage/sortie will go down. Someone bombing GVs in a Lancaster is clearly not doing it for score and not even perks (Lancs have low ENY).
And even for the few bombers that have "attack" mode (like Ju-88, B-25C) you don't gain much, especially not at the top ('frontpage') ranks - your damage hit % will again go down with each drop, and kill related score categories are just a part of your attack score.
I bet if Lusche posted the Air to ground kills the A-20 followed by a bunch of american bombtrucks would be top of the list
In the current year's list of A2G kills, the A-20 indeed leads (1.9% of all GV kills), the Il2 is #4 (0.91%), the Lancaster #5 (0.90%). The next heavy bomber is the B-17 at #23.
In my (subjective) experience, relatively few GV kills by the Lanc come from carpet bombing spawns or friendly towns, but attacking enemy bases (mostly ports/vbases)