Showerthought: I clamped a dovetail jig upside down on a white oak drawer and got the tightest joint I ever cut
Was knocking out a set of 6 drawers for a kitchen in Dayton last fall and grabbed my Keller jig without checking the orientation. Ran the whole drawer that way before I noticed, and it still fit better than the ones I cut "right" all winter. I think clamping from the back side let the bit ride the grain instead of fighting it. Does anyone else flip their jig on purpose or did I just get lucky on one drawer?
Let the bit ride the grain instead of fighting it" sounds like a story that feels right after the fact. One drawer is not a pattern. Run twenty that way and track the fit, then come back with data. My guess is your stock happened to be flat and your setup was dialed that day, not that the flip did anything.