wrong scaling after maintenance

I have the SC-2/420 and WinNC-PC.

After cleaning the machine has a scaling issue (well, I needed to disassemble and assemble parts of the machine for that).

Had to change work piece zero-point for the x-axis after this maintenance in order to match the old work piece positions, weird but accepted.

But what is bothering me is that travel along the x-axis is 1.55% off now. E.g. in order to travel from 0mm to 64.5mm I need to travel to 65.5mm in WinNC-PC now. This is very reproducible with multiple gcodes over various work piece sizes and multiple runs. Previously travelling to 64.5mm was just that: 64.5mm.

No changes to WinNC-PC or the gcode made other than the work piece zero-point.

Any hints off what could be wrong? (I know that I could set the scaling but that sounds like hiding a machine problem).

Bernd