No, it's all about the officer's speeding process since a number (batch) of X applications is assigned to X officers by batch arrival order. Still first in, first served but by batch.
By ex, if they receive 100 applications (#1 to #100) for 10 officers (1-10), they assign files by batch to each officer. The first batch of 10 applications (#1 to #10) to officer 1. The second batch of 10 applications (#11 to #20) to officer 2. Batch 3 applications (#21 to #30) to officer 3..... etc.
Faster the officer works his batch, quicker the applicant receives his AOR.
Your application could be in batch 1 but delay due to absence or laziness of the officer and your application remains under the pile for a longer time.
Just to say the process is all about how fast the officer works his batch of file; but applications are assigned by batch arrival order.