Your description is describing sync and it doesn't solve the problem. I know this because I have implemented sync in this way. I've spent some time looking at this. It's also what Jared tried and, as I predicted, didn't help.
What is needed is a way to determine a different offset, between where the scope is commanded to go and where it arrives This is the correction that Frank made. It is not the same as the difference between where the scope reports it is pointed and where it is actually pointed.
Trying to do something about this, applying what Frank did - an offset to the slew position to compensate for this difference - is possible.
A competent developer could develop an ASCOM hub that did this, and any extra corrections that people feel are necessary - there will be!
But I think it will be a support nightmare, regardless of if it's done in an ASCOM driver, in a separate hub, or in SGP. Every mount will be different, it will be difficult to get meaningful feedback, and the act of doing this will further raise expectations.
But if people want to prove me wrong then please do so.
Chris