I have been using hyper glide mouse feet on top of my original mouse feet (without removing the original feet) on my G400 Logitech for a while. Once I removed the hyper glide mouse feet I immediately noticed that my sensitivity felt faster (with additional mouse feet 1.073, without additional mouse feet 0.96 feels the same). Is it normal for additional mouse feet (high lift off distance) to cause sensitivity to be lower than the mouse is intended? Thank you for your help.

I haven't really tested this with my machine yet, but I imagine if this were the case the mouse would feel "jerky" since it's missing reports.

I'll test it sometime.

i've done this with other mice before and yes the mouse felt "jerky" and definately felt like it was missing reports. But the G400 that I am using has a much higher lift off distance causing additional height to be playable and smooth still (however, the additional height definately feels like it is slowing the sensitivity, maybe due to the sensor resolution getting zoomed out?)

mice have an optimum lift of distance, by adding extra feet your most likely out of that range.