...Each time PCB was dismounted from a CNC and mounted again, it will have some angle of rotation over a zero point (X=0, Y=0).
Manual measurement of this rotation angle is performed with help of laser module mounted on the same CNC. For each reference point, travel CNC with a laser module and fine tune X/Y coordinates to target at the center of a drilled point (laser light will dim out). Write each of the measured point's coordinate with corresponding ideal (original) point coordinate into the reference point (text) file. Then use this utility with source G-Code file & measured reference file to perform transformation into a destination G-Code file. ...