Might just be the conductor, not everyone can go at exactly the same tempo. Like how 2 pro musicians have different styles and sounds, 2 conductors will have different tempos and techniques. Even the same conductor years later will be different. I feel the only way 2 performances will have the same tempo will really only be with a met. Like my style has a lot of excitement and/or flow (depending on the setting) to it, this I’d go at slightly faster or slower tempos than this one. Plus I might just have a stylistic choice to have the tempo at a slightly different place, just a ton of the art to it. Hope I explained this somewhat well lol.

You could compare this version with the marine band version conducted by the same director

The band is not actually smaller than it ever has been. What you are noticing is that Haithcock and Fettig have chosen to use "wind ensemble" orchestration for many pieces, and more frequently, in the past couple of years, rather than "full band." This is not uncommon....it's basically one to a part (unless greater numbers are needed in some sections). This is how the Eastman Wind Ensemble is set up. The numbers for the band are the same now. The parts and assignments are decided by the director with input from the applied faculty members of each instrument.

this is not the full ensemble :)

It isn’t. But they’re much more flexible-using different-sized groups for each piece.

personnel change depending on repertoire