Alternative for "as high as" for an academic text [duplicate]

The editor is right to object to your phrase, or at least, I wouldn't use it in formal writing either. It might depend on the field but it just doesn't feel "right" to me. I don't, however, agree with the suggested alternative. I would instead suggest you write:

A is ten times the height of B.

That clearly and unambiguously means that the height(A) = 10 x height(B). You haven't given any context here, but depending on what you want to say and what A and B are, you might also want to consider:

A is ten times B.

A is greater than B by a factor of 10.

Both A is ten times as high as B and A is ten times higher than B can be used. Although one may think that the latter means A is eleven times as high as B, it really means the same as the former.

I imagine that here A and B are walls with different heights, in which case you can write A's height is ten times B's to make things crystal clear. If they are numbers, you should just use A is ten times B.