Since I have a SignVideo PA-200, and DataVideo TBC-3000, I rarely used the AVT-8710 proc amp.
But, once upon a time, 10-15 years ago, I did use infrequently. Since it was pretty limited, I mostly used it to drain all color from B&W videos. At most, maybe tweak +1/+2 or -1/-2 if brightness was off, when going direct to DVD recorder (LSI JVC). I keep all values reset to 0 these days.
I only used the AVT-8710 proc amp for my hobby videos that I can remember, it was never powerful enough for my restoration projects work.
And since we're talking proc amps, I'll add this too: I also have the Elite Video BVP4+, but it can be too powerful, the opposite of this TBC. The BVP4 also has some side effects that can degrade already-good video, much like the ES10/15. So it's only used when required, when the net effect is improved video, digital artifacts are better than the analog damage.