Does anyone know if D2Maxroll's double throw IAS calculation is accurate?

I'm messing around with upgrading my merc faith from fana 13 to fana 15, and d2maxroll states the ias double throw is the same.

Gear on the barb for the curious:
gface, lacerator, warshrike, highlords, enigma, loh, gores, razortail, dual leach, ravenfrost