Let's say 100 applicants applied in January:
10 may get AOR in Feb (group 1); 50 in March (group 2) and 40 gets theirs between April and May (group 3). Apps are forwarded to their respective local offices.
Factors that come into play: number of apps received by the local office; capacity of local office; agents experience; application particularities (travel history, nationalities...) etc...
It may happen that some in group 3 get test invite before group 1 and some in group 2 got FP but still get test invite before group 1; then some of group 1 gets DM before; while some in group 2 get oath before the ones who get DM. You can use any combination. I'm saying all that to say this: while it's ok to compare timelines on the spreadsheet, but we have to understand, even if 10 applicants have similar profile (same municipality, number of days, travel history, age group (test or no test), etc.), there would still be differences in timeline.