Either its bad or appropriate that you have a Sig on a glock stand or its naturally above a glock....lol.
It took me little to get my Romeo Zero zeroed?...lol. I managed but I started at 5 yrds to get on paper. Then pushed out to 10. I will be trying to zero the Holosun this week and use the same technique. I'm not really an optics guy except for my rifles. ACOGs through Aimpoints are all zeroed for 300meters. I was surprised I could zero the Aimpoint out that far. Its not a scoped one with magnifier, just red dot.I threw a romeo 1 pro on mine... I can't seem to get it zeroed.. but I've always had trouble with pistol optics
Might take it off and sell the optic and run normal sights