Well technically the ER versions of Megatron are a different mold, so it's only really 6 instances of this mold being in use. Even though it feels like more. That said, 6 is still a lot. And THAT said, the ER and Siege molds are REALLY similar, so yeah, we might as well call it 9.
I think the percentage is more 75% new part, 25% inherited from Siege, perhaps as high as 80% new.
It's a LOT of work for very little cosmetic change and I think most of us would agree the Siege version is the better toy.
I would love G2 Green and Purple Sieges but I don't think that'll happen now. I'd have been much happier buying those than multiple grey versions. And the Perfect Siege Megatron looks no different to the Netflix ones.
And not one single version of the siege version has been clean. Original flavor: battle damage Second go: cell shaded Netflix #1: silver paint with battle damage Netflix #2: identical to N#1 Premium: essentially identical to N#1 and N#2
And IMO, none of them do it better than TR did, which did the same thing, plus has a really good jet mode, and can attach the cannon on his shoulder.