I feel like when the time is right, he'll stumble assbackwards into a way for people with too much mana to do basic spells. I don't think this is how that portion of the spell even works, but for an example if the problem was that the number of offerings was some predetermined percentage of their total capacity, then people with way more total wouldn't be able to pull off the spells by saying the same amount of offerings as people with average capacity because they're still overfeeding magic power into it by much more than the tolerable variation allows for. Y'know, where someone else could maybe adjust by going up or down by one offering, even if someone with a lot more magic just straight up drops it to 1 it still might be too much. So, if someone like him made an offering of 0.25 instead of 1, perhaps that could make a difference in that case.
Clearly thinking way too hard about a hypothetical even I don't expect to be the actual scenario that would unfold.
TL;DR: I think something along the lines of modern math might revolutionize this spellcasting business.