Modular Synth Panels

Hi - I just took delivery of 25 panels I ordered from Schaeffer in 
Berlin. They look fabulous with silver engraving on blue.

However I was a bit disappointed that one of the panels is a much 
darker shade of blue than the others - it's very noticable when the 
panels are sided by side (as they will be).

Has anyone else had experience of this? I have emailed Schaeffer, but 
have not had a response yet.

Godric