I am not sure why the results are so inconsistant but as other have said the speakers/crossover should be set to small and start with 80hz.
I don't know your speakers but from the spec. they should be able to do better than 60hz, so 80 hz is a good starting point. So I guess your hitting the limitations of accuEQ
120hz may be part of your localisation issue and if 80hz is still causing issues try 60hz
Oh, I've never had any of my current speakers' crossover set to 120Hz, so I don't believe that the localization would have been because of that. I am convinced that the localization issue had to do with reflections more than anything else because where my Subwoofer is now, I am not able to localize to sound.
I have also never set the speakers to "large" - the only way to do that on my Onkyo AVR is to go into the crossover setting in the menu, and lower the crossover number until you get to the "full band" option. AccuEQ has never set it to "full band" after any of the calibrations I've performed, and it probably would only do that if I were to indicate that there was no subwoofer prior to AccuEQ taking the measurements.
Because I had the Polk RTi A1's as my Front LR's up until a few days ago, they had been set to 80Hz (their Frequency Response spec is 60Hz - 26kHz). When I moved them to surround duty, and re-calibrated once I had the new RTi A3's set up, AccuEQ did determine a crossover for the A1's, even as surrounds, of 60Hz as it had done when I had them as my front LR speakers.
It's only today when I was experimenting by moving my Sub back to the spot before (when I was having localization issues) that AccuEQ decided that my RTi A1's are less capable than they are. In fact, it even thought the Polk RTi A3's should have a crossover of 200Hz (their FR spec is 50Hz - 26kHz) when the first re-cal was done after moving the sub.
So the question is, again, if I know that the RTi A1's are capable of handling an 80Hz crossover, is it fine to ignore AccuEQ telling me that they should have a 120Hz crossover - despite having previously-determined a 60Hz crossover even when I first set them up as surrounds - and set it lower even though it's generally not advised to do that?
I think this is now less of a localization issue, and more of a "why is AccuEQ acting drunk?" issue.