Sealed top layer?

So why is it that every surface on a printed model seems to be sealed unless there is a flat top surface... in which case the M200 seems to print a fine lattice that isn't completely airtight and doesn't react particularly well to ABS smoothing.

It's frustrating. Am I missing something?

Pictures please.

Umm, I dont have anything at hand at the moment, and I'm not sure I would be able to get the fine lattice structure in focus on my camera.... 

Do you mean to say it's not something you have observed when printing?