GURPS Power-Ups 4 p 17, this deals with a leveled enhancement which is at maximum effect at lowest level, minimal effect at highest level, when based on a leveled advantage.
Ascending Limitations are an inverse interpretation of this, where a limitation is minimal at the lowest level, and maximal at the highest level.
By treating leveled enhancements as leveled advantages, you could also apply declining enhancements where they scale in respect to another leveled enhancement on an advantage rather than a leveled advantage.
Inversely, a limitation which is minimal during the 1st level of an enhancement could ascend alongside an enhancement as it ascends. For example: an innate attack which begins as very Accurate which gains Inaccurate as increased levels of range or area affect are chosen.
This is comparable to Alternative Enhancements, too.