A member of my guild has stated that fire resist, and all resists, work on a tiered system by quoting http://www.worldofwarcraft.com/info/...sistances.html . I don't think it's entirely unlikely but i don't necessarily want to believe it without confirmation. Anyone know the answer to this?

I'm pretty sure that there aren't specific break points on resists. You scale up gradually as your resists increase up to a maximum of 75% chance to fully resist.
Also, your link has an extra period at the end.

Your guildmates are mistaken, however many others have reached the same incorrect conclusion by looking at the table. They need more math classes ;).

Resists aren't tiered at all, they scale up with each point up to the current cap at 315.

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