There are no "various" versions. Whether you select yards or meters for example, the calculations required are handled in the firmware.
The question remains, is it accurate in its readings? The readout is no more than ± one digit with the Labradar. They don't play well together, but ten shot averages fit the ± one digit. Comparing the TBC to the small one offered by FX, is an act of futility due to the acoustic triggering method. Incidentally, the Labradar uses an acoustic trigger, so unless you activate the radar before taking the shot, there will be a larger variation in velocities measured between the two units.
The meplat (flat nose) of airgun slugs, is the main reason the RA4 (round nose, 22LR ballistic profile) falls short at extended ranges. Bob Sterne and others are working on establishing a better profile for both slugs and pellets. Let us hope FX listens?