Found some rust spots on the roof with fingers growing out of the middle(like crows feet). They are small about 0.5cm in diameter, but causing some concern to me. Looks like caused by stone chips which had been neglected and getting bad. Is this in-out or out-in rusting? I may have to do a bare metal sanding and respray soon to stop it once and for all. Have no proof that they are growing in size, but one spot seems to be bubbling every few weeks like gas buildup then it flattens again, means that it is the actively rusting one! This shouldn't be happenning to a Mercedes Benz car at all? I am second or third owner so don't know of any previous roof damage work done. HELLLLLP!