The scenario you describe doesn't make sense to me. If you can win a 'B' World Series, then you should dominate 'B' level competition in your area. I don't see how a team could dominate its local 'B' competition, yet be dominated by the local 'A' competition.
I can't imagine there being such a clear divide between 'A' and 'B' in an area. If there's 25 teams playing in an area, how does it happen that the difference between #8 and #9 can be all that wide?
If your team has a .500 record or better vs teams a class higher, your team should be playing a class higher. Easy as that. It's about competing not trophy hunting.
As far as a large gap between "B" and "A" -- my experience (mid-Atlantic USSSA ball) is that the difference is huge. DD's team just got back from USSSA Eastern Nationals in Ocean City where we played in the open bracket. We were 3-0 against "B" teams -- but 0-3 against "A" teams with two mercy-rule losses and a total of one run scored. Of the three "A" teams we faced, I would bet two of them would beat DD's team in 20 of 20 games. The other one would probably win 17 out of 20. So it seems to me the difference is huge -- but maybe that's because we are not a top "B" team.
They have a B team at #11 with a 42-9 record. This should be an A team.