Well, the short version of this is that “it depends”. Your way of working doesn’t give you any more accuracy unless someone messes up along the way.
I have had plenty of projects where the timeline is completely “standardized” for the project. Tone always at 00:58:30:00 to 00:59:30:00 etc. In those cases it’s entirely foreseeable what will happen when the start time code changes. And since the start timecode is given the offset is really the point. So even if content doesn’t actually start at 01:00:00:00 as expected, but three seconds later, it really doesn’t matter in a lot of cases. Because if what I’m doing is stringing out a bunch of 5 minute shorts every 10 minutes, the main issue is sync between audio/video, the latter included in the AAF which will move along with it. So it truly doesn’t matter if I import it as is with the AAF’s start time of 00:58:30:00 and content beginning at 01:00:03:00, or shift it to 01:18:30:00 with content beginning at 01:20:03:00. Same difference, with the exception that after the import it’s in the area where I want it.
So no accuracy is really gained by not doing it that way.
And as a personal anecdote; In December through February I worked several long days on NHL “featurettes” that were all strung out on a timeline, and the AAFs all started exactly at 01:00:00:00. Being able to quickly copy the timecode for the start of the next piece and paste it into the offset window during import was way faster than having every one pop up at 01:00:00:00 forcing me to navigate to the start, making sure I copy it all, navigate to the new time-slot and paste. When you’re doing spot number 35 or whatever at 03:15:00:00 or whatever it’s far easier to me to just offset during import.