All seems to working correctly with regard to all 3 formats, MIFF/PFM/TIFF, in my tests of the FFT phase image under IM 6.4.1-5 Q16 HDRI. All three are now reporting values between -pi and +pi
Thanks for fixing all of these formats.
Just a note: Sean Burke and I are now implementing some other FFT supplementary functions to the base FFT and IFT from my prototype scripts. We now have working blur and deblur using FFT (the equivalents of convolve and deconvolve but done in the frequency domain). These have been tested successfully under HDRI and Sean reports that it also works under non-hdri. I have confirmed them under HDRI, but I cannot get the non-hdri FFT to work. Sean is looking into this.