You literally restated what I said in a way that makes it seem that I'm incorrect.
The offset is applied to the whole boost curve (which the 10-20 series both have) it doesn't magically vanish when the card boosts past it. I'm going to quickly pass over how GPU boost works, because you seem knowledgeable, if obtuse. As long as there is thermal and power headroom, the GPU boosts as high as it safely can. It does so on a curve, but it does so very aggressively. When the card hits a certain temperature it stops boosting and slowly ramps down until the temp settles.
So my 2080 (when it was on air) would boost to 1965mhz with zero overclock.) It would slowly decrease until it settled at 1875mhz at 65°C. I liquid cooled it and it would hold it's boost much better even boosted higher! It would boost to 2025mhz and settle at 1950mhz at 45°C. This is still with no overclock, just GPU boost technology. Now I then managed to get a modest overclock of 150mhz with a slight undervolt as well. Boosting to 2175 until it reaches 45°C where it settles at 2150mhz.
The offset value is not "useless." Until OP tests it and it is applied to his standard GPU boost we won't know if it's stable, sure. The offset value will directly correlate with his GPUs boost clock so long as temperatures are sufficient. So no sir, I'd have to say "Clearly you don't understand how GPU clocks."