Did they use a white primer on all Panther black Fords?

Does anyone have an idea why,

My car is in good condition for 10 years old ( Focus ) but keep finding white specs all over it, which is infact a stonechip where the lacquer, basecoat has been removed showing the white undercoat!

Ive found spraying a bit of black paint on my finger tip and touching the chipped area hides it but is there any other methods? are those chip sticks any good?