Thanks all, just to follow up...
The dirt doesn't just show with the 16-50, I now see it with every lens.
If "dust map" is the same as Dust Alert then yes, the K200 has it and I've been using that and Dust Removal with good results until now.
The only repair shop left 'round here charges $50 to thoroughly clean the chamber and sensor. They also offer a deal where they clean monthly, quarterly or annually for a set fee. As I said, 1-day service is additional and worth it to me as I only have 1 dslr body atm.
I investigated some more and found my blower is contaminated, I don't know how or why. I used it on an old filter and it's spewing an oily residue. It's an old, cheap one and now lives outside in the useful junk pile