I didn't say I went from 1.3 to hypoxic. I went from normoxic to hypoxic in 90 seconds. There is a difference.
The only reason that I can think of for diving a CCR with a normoxic gas is during air breaks on very long decos. And anyway, the diver doing so should be very on top of his/her ppO2, even more considering that it is a mCCR.