I don't know anything about the routines, but if it were me, I would print out the coefficients from each program and compare them.  One thing you might do is print out what is before the binary point and what is after as separate values, and also the complete value in hex.  If you're correct, then step through the conversion and print out the values at each step to see where it goes wrong.  Might take 20  minutes to make the program print correctly and 20 seconds to figure out what the mistake is.

Good luck!