Allows you to dual-wield weapons with up to 7 ap-cost for the first level, and hold double-handed weapons in one hand at the second level.

skullcrusher AND gutsplitter

I think the minimum level requirements are not necessary, because anyone with cleave lvl 2 must have spent 6 skill levels = lvl 24 minimum. Add 8 levels for the Barkskin requirements, makes level 32. At that level, you've likely invested already 1 skill level in Fortitude and 2 in Combat speed so changes are the first level of Giant Strength comes no earlier than level 44 -> that's way beyond the proposed level 25.
The requirements for the second level only add 3 hard hit, so you will get to that when you're level 56 - pretty much the same as the proposed level 50.