[GaryVoshol]

You are correct, the teams are put into pools A/B/C based on team number - and team number only.

At least in your regional, all the C list were rookies. Look at the GLR pools if you want to see the perverse conditions this creates. There were only 2 rookie teams, and 1114 was put in the C pool because 1114 was 2/3 the way down the list. This meant the two rookies could never be allied with 1114, but might have been opponents (it happened they weren't). 70 was a A, while 494 was a B, and indeed they were allies once and opponents once.

Given that pool setup, the assignment of "one from A, one from B, one from C" was randomized more than in the 1st week assignments. 1188 played with 3 teams twice, and played against 2 teams twice. There were no other duplicates. I understand other teams had more duplicates, but no one had a perpetual partner or opponent. In smaller regionals, to keep match timing somewhat separated, the duplicates are higher.