Never Been a time limit before...
I work at the training center in Dallas, and I can tell you that no one in the pool has had to re-interview. Back in the 90's, it was common to wait in a pool for 6 months to a year. That was back when none of us could find a job, then around 1998, demand started exceeding supply, and the pool went away. Guess what, thanks to UBL, now supply is back to exceeding demand, and there's a pool.
For the March group, keep your fingers crossed, the board meets on April 24th. Good Luck!