If your error doubles after you compute a PEC curve and program it having checked that "Data was collected when telescope was pointing West", just uncheck the box and recompute the curve and reprogram the mount. I always reboot-normal my mount after programming PEC as well. If you told me the checkbox is backwards I would not be surprised. It was certainly backwards at one time and I did complain about it, but I do think they either ignored me or told me I was an idiot. You tell me which!
