S50 and ELO Touchscreen

I have setup 10 work stations consisting of a S50 and an ELO ET1937L. 3 of them calibrated correctly while the other 7 have the y-axis reversed. They all have the same firmware and drivers. When I first turned on the 3 that work both the x and y-axis were reversed, but calibration worked. The 7 that do not work had the x-axis correct but the y-axis was reversed. After calibrating these it did not resolve the issue. Has anyone had this problem? I'm at a loss.

Thanks for your help
Tyson