I have a Professional in a very nice paintscheme that has more or less the same issue. Paint looks absolutely spotless on the rest of the frame, but on the toptube there is some rust located caused by the cable. I were thinking of stripping the toptube one day and give an artist the opportinity to make an artwork on it. Accurately matching the colour of the rest of the frame would be a pain and giving the full frame a repaint is a no go.

Nice bike btw! Enjoy it.