Magic Resistance has issues

[Carl Minden]

So I was looking into subraces since they were added recently and noticed an inconsistency with the way they were handled between the core drow race and the subraces with magic resistance. As described by the documentation Drow have "a natural 50~ magic resistance associated with their drow physiology and gain a +2~ inherent bonus with every character level."

The way this is implemented is 50 natural res at character creation and then 4 inherent res at every level starting at lvl 2. As described by the docs resistance works like this: "the final applicable value is determined by taking the largest armor or resistance value and adding to it half of the second largest value, a third of the third largest, a fourth of the fourth largest, and so forth." This seems to explain the slightly weird fact that Drow get 4 inherent magic res each level, resulting in a total magic resistance of +2 each level. There were a couple inconsistencies in the way this was handled in the subraces which I have corrected to be consistent with the drow implementation.

Once I had made this change and was testing it I noticed that while the implementation of the resistance stacking seemed to work for Drow in my testing it encountered issues testing the magic resistance values for grey elves, for example using my updated grey elf resistance formula a level 4 grey elf has 25 natural resistance and 30 inherent resistance by the rules as in the manual this should result in 30 + (25 / 2) = 42.5 resistance (rounded to 42 because ints) but the current implementation results in a final resistance value of 47.

I have fixed these issues in my fork of incursion but testing it made me realize an issue with this implementation of the subraces resistances so the description of Grey Elves says they have 25 natural res and gain 5 inherent every level, so in order to make this consistent with the Drow implementation, Grey Elves gain 10 inherent magic res every level starting with level 2, but this breaks down after level 3. At level 1 Grey Elves have 25 magic res, at level 2 they have 25 + (10 / 2) = 30, then at level 3 they have 25 + (20 / 2) = 35. So up until now they have been gaining 5 total magic res every level, but at level 4 the inherent magic res becomes the largest resistance bonus so the total res becomes 30 + (25 / 2) = 42 meaning the +5 became +7, and then +10 on subsequent levels which is a bit weird.

So I'm not really sure what we should do with magic resistance it clearly seems broken and inconsistent as is, but my solution seems potentially a bit overpowered for the new subraces, any thoughts?