Stealing with small pairs Late Position, Levels 1-4

I play the PP $11s.
About how often should I be raising with small pairs, in Late Position, with 1 or 2 limpers already in? I understand you'd normally play these for set-flopping value at later levels only. But suppose it is late 2nd level, and you have not played a single hand waiting for the premiums. Isn't it worth it to milk the tight image some percentage of the time? Where's the flaw?