Red Mage - Fast Cast IV ... Really?

I've been to the ffxiclopedia website, and noticed it advertising on the RDM page Fast Cast IV, can anyone confirm or deny if this is try, as I'm 77 RDM and have tried to test it by casting Gravity and then immediately checking the recast time with not Fast Cast equipment, and it goes from 60 seconds, to 52 seconds which makes fast cast's recast time about 13%

Surely this can not be right?

By the way, this is without Composure up.

Fast Cast IV

Casting time -25%, recast -12.5%

sounds right to me.

u sure ur not wearing any fast cast? lol.

Nope, my maths are messed sometimes, so I thought I'd ask, thanks. :)