But abstaining from this question appears to have affected my compass result. It appears to read it the same as “about the same”. Which isn’t what I said or meant. There are a few I abstained from and I think that by doing so, it has put me a lot closer to center than is probably accurate.

Yeah I noticed that once or twice too. I would have thought saying "I don't know" should have made it disregard that question, but it doesn't seem to.

I don't know if that's because they're explicitly treating it like "about the same", or if it's just that the way it works is you start in the centre and each answer adds or subtracts a certain value from your score, which has the side effect of it being the same as "about the same". A better system IMO would be a sort of weighted average of your non-idk answers, if that's what they're doing.