As I stated in one of my previous comments:
To put it in quantitative terms as is otherwise not possible due to the qualitative differences:
Say the normal universe has a tier value of X
Say Superman has a tier value of X * 100 which we will state is equal to multiverse level+ (2A)
When translated into the Sixth Dimension:
A Sixth Dimensional Universe now has a tier value of say γX
Superman now has a tier value of γX * 100
Superman has been scaled up in power in the Sixth Dimension; however, everything else is also scaled up as well. The difference between Superman and the universe he inhabits remains the same in the Sixth Dimension as it does in the regular universe. He has not gained any relative power. In this quantitative example the multiple of 100 remains the same in bother layers of reality so there is no difference. If you were scaled up to be a geometrically 5D being, but everything in the universe was also scaled up with you, then from your perspective nothing has changed at all.
This means that if we do concede that Superman destroyed the World Forger's multiverse in the Sixth Dimension, it is still only a 2A feat. Regardless, this does not matter as Superman already has 2A feats so this would change nothing just being more supporting evidence. The problem with putting this on his page, as previously stated, is it will cause too much confusion.