Cosmic vs. Cosmic (ala Kryptonian vs. Kryptonian?)

[cosmicfish]

Originally Posted by Sunrunners_Fire

IT:DR (/1,500,000,000,000; Bane (Occasional), -5%) [1,733.75, rounded up to 1,734]

I may be missing something - in Powers Injury Tolerance: Damage Reduction only goes up to 1/4, and it appears to have a cost of 25X for a 1/X reduction. Where does this formula come from?