Progression from 7A to 7B

There is no rule here for promotion / hike. All depends on your manager and client. Usually they won't give you unless you are very friendly with your manager.

If you consider time spent in the band , you are eligible I guess. But business needs are the most important factor for promotion. Have a candid conversation with your PM , and see how he responds. If you feel there is no scope to progress switch internally or move out .

I got within 1 years based on client feedback

I had to put down my papers to get the promotion. Else not sure when I would have received.