So far the numbers calculated via the info in that thread have been 100% correct for all cases where I bothered calculating the res%, and that was for high lvl and lower lvl ressers, and in C3 as well as in C4. Maybe they change something about the WIT bonus for res in C5, don't know. Was the char you ressed fully in lvl 75, or did he delvl when he died? If you delvl and get ressed, the % numbers you see on the exp bar are misleading, because the exp loss (that is, the actual number of exp lost on death) are calculated based on the higher level.
If the info in the res% thread still holds true for C5, you definitely should get a maxed out res on a 75 EE with that equipment, i.e. you should hit the +20% hardcoded limit.