Yeah if set to auto nvidia drivers are controlling it or px1. If you set a voltage in CT then it will stick all the time no matter what is in px1 or afterburner.

I set it with CT and still set a curve in ab. Just grab the 1.093v dot and set it to the max clock you want and hit apply.

No you do t have to match.. it will ultimately use whatever voltage in the classified tool.. I just use 1.093v cause of habit in afterburner. But it dont matter what voltage you use in afterburner as ct will overide.

Ab will report whatever voltage you set in ab on the osd even though it's not right.

Dont make sense.. lower voltage can cause lower scores. Try upping the voltage a tad and see.. too much for me with cause errors in 3dmark.

My card scores best at like 2160/2190mhz. +1369 mem. That's at 1.1375v. That's for firestrike. Sure will be different for other benches.

I think its best to avoid 3rd party apps when using the classy tool. Especially when it comes to gpuv/nvvdd.  I would first emulate w/e curve you are used to with manual settings. That being said AB can work with Classy.
 
if your AB curve tops out at 1.125v @ 2190 I would throw 1.125v in classy NVVDD and LL 0 next +what ever sum of 15 "clock increments" gets you to 2190mhz in PX1. Followed by validating that manual perf is within margin of error with AB Curve perf in GT1 of TS or FS. Just look at the FPS and see how close the FPS is.  If its not within margin get the DMM on KPE RTX NVVDD and verify NVVDD is actually what classy was set to.  I have experienced from time to time that NVVDD is not actually applying after attempting to set in classy. The DMM tells me immediately.
 
If you find with DMM that the card is not actually taking the classy NVVDD setting I found that either opening PX1 or shutting down and turning off the power supply followed by a cold boot, back to Classy to set nvvdd resolves the issue.
 
15 mhz increments so if base is 1350 and you set the clock +15 it should goto 1365. As long as you are holding <40c under load.  like if I wanted +100 clock via ab curve or PX1 I would not set +100 as it is not linear value that the boost algorithm can work with. +90 and +105 are. +120 ect... With KPE and classy curve is kinda nonsense. As you are setting the voltage via NVVDD. Only things that will interfere with desired clock boost are PL and thermals. PL obsv removed if a certain bios is being used.