Two interrupts of the same priority won't run at the same time. So there is no need to disable/enable one. The ISR that comes second will just wait until the first one finishes.
Since it is a fixed ratio 20/1, and single UART channel, it would be prudent to have only one 2000Hz interrupt, counting 0-20, and on 20th time to request both infos. Hard to say more without seeing the code.