Thinking out loud here, Could this be the end result of the Aux pulley being out by 1 or more teeth and correcting for it?No, it shouldn't. When the timing belt is installed, aligning the cam pulley timing dots, and aligning the aux pulley are two separate activities. Address each one separately, and get each one correct. But making a change to the cam timing should not affect the aux pulley timing, "IF" you pay proper, separate attention to the aux pulley.
All too often, people put paint marks on the old belt that align with similar paint marks applied to the pulleys. Then transfer those marks to the new belt and install it the same way. All that does is preserve the old timing, even if it was wrong. And then, if a subsequent change is made to the cam timing without paying separate attention to preserving the aux pulley timing, then yes, changing cam timing could result in changing the aux timing. But that's because the cams and aux were not treated as separates and timed separately; and NOT because there is some sort of "physics" connection between cam and aux timing. They're separate, treat them separately.
I strongly recommend not marking/ transferring marks when installing a new belt. It is not difficult to time the engine, both cams and aux pulley/ distributor, from scratch. Do it right each time, and don't just transfer previous mistakes.
This is my intention.