I can easily understand your frustration. However, mine flips very reliably, I would say. It was a very long time since I had a problem with it. I've set it to flip at 2 degrees, I think, and have set the Goto limit at the meridian (don't know exact values right now, but with western limit say 110 degrees, Goto is 20, so any goto after meridian should trigger a flip). I hade issues before but more with run-away slews - disappeared on upgrade of Gemini firmware to the "beta" version that is around.
Anyway: if you fiddle with the driver, I'd be happy helping you out testing!