Jackie was acting boss for a period of time. Then Nicholas Corozzo got released and became acting boss. The feds report them running the family together at the time. As Acting and Street Boss respectively.

Like Jackie, Bellomo was an acting boss first before the position of street boss ever existed. Matthew Ianniello was acting boss while Bellomo held on to that power he had as acting; effectively becoming the family's first street boss.

Colombo gets kinda convoluted with all the wars and such. and they're definately a family in crisis. SO I can't extrapolate that I know what's going on there.

As Mickey Meatballs said, sometimes they roles are held byt eh same person. I would think that especially in a time of leadership crisis that this would be more imperative than ever. With the feds keeping eyes on them all the time it's hard to be as rigid and hierarchal all the time, in this age more than ever.

EDIT: Fixing grammatical erro