How do you know that the controller actually computes 32 bits of accuracy?
For that matter, where in the hell do you find a motor that accurate? Even with a tach and PLL, that's a strong statement to make if it has any kind of bandwidth (i.e., how many years are required before its operating point actually stabilizes to the parts-per-billion level?).
It's also more-or-less impossible that you have a nanovolt-precise analog signal, so there's no way to start with a 32 bit number, convert it to a voltage, then convert it back to something digital (like a tach speed) without throwing away about 12 bits in the process. Analog around 12 bits is precision, under 20 bits is difficult; there are 24 bit converters out there, but the LSBs are a good source of noise and not very coherent with the signal anymore. 32 bits is essentially impossible, unless perhaps you're NIST and everything is bathed in liquid helium.
Most importantly... what will you ever be using it for, that will need 32 bits of accuracy? Can you visualize a situation where that's ever a concern, let alone possible? 32 bits out of an entire meter is the width of one or two atoms! It's possible to resolve positions that fine (STMs and such are capable), but not on that kind of scale!
Tim