Philippines Official Overprint

This is Philippines nos. 591 in Scot. However, it is not listed anywhere in Scott as being overprinted for official use. The 1c, 5c, 10c, and 20c from the same series is overprinted with a different style of O.B. overprinted, but this is listed no where. The style of O.B. overprint seems to be different from any listed. Is this a stamp Scott missed listing or is this someone putting an official hand stamp on stamp not intended for that purpose? Any ideas?

I have heard that the Philippines is notorious for people doing philatelic phavours in order to sell more stamps. Perhaps this is an example. Curious, never the less.

This was a common practice in the Philippines. There are many different variations in size & colored ink starting around 1906.

OB = Official Business

Try this link!
http://www.philippinephilatelist.ne...Updates.html