I’ve taken a look at your FIR Designer project file. It generates a minimum-phase FIR filter so the approximate delay through the filter is 0ms and is why you’re seeing no roughly the same latency with the FIR on & off.
Also, it’s generating a FIR filtering using the Auto Mag process with no smoothing. This is generally not a good idea. Fine resolution filtering like this may make the measurement position sound better, but will sound a lot worse in all other locations. We recommend some measurement averaging and Auto Mag smoothing.