It doesn't matter whether the limit is hundreds of thousands or just hundreds, at some point there is a limit and they're in danger of hitting it.
https://en.m.wikipedia.org/wiki/Integer_overflow
Simply put, as a concept, if the maximum it can handle is 999,999,999 and you make it do something that adds to 1,000,000,005 it has nowhere to put that additional 1 and it does not compute. Your damage is now 5.
I'm pretty sure they talked about something that would line up with this issue when they were first announcing their plans for the stat squish.