When 'new part painting' weld-on panels, the Audatex paint system will generate an overlap of 100mm into adjoining panels. This is to accommodate for burn and fitting damage etc.
The overlap will provide 100mm of preparation, primer, basecoat and lacquer (subject to the paint type in use). Therefore if the 100mm is considered insufficient to finish, the adjoining panel should be marked to blend.
However it should be noted that on many modern vehicles lamps, bumpers and other panels etc. often cover the panel joints. In these cases, agreement must be reached with the work provider on the necessity to blend.