If our opponents are tougher, than while it is true that we end up with a likely lower score than our opps, the reality is that we only played 4 or 5 of those opps (maybe not even any of the "tougher" ones). Since with a short format, you cannot play the majority of opponents in your section and the assignment of opps is random, why not just score across all sections and assign points as if in one big section? The reason this is not done in ACBL land is twofold: 1) The sections and number of boards are usually devised so that you play the majority of opps in your section. This makes it fair as you and those playing your direction have the same quality of opponent. 2) The number of duplicate boards is fixed and to have a section of 60 would not work logistically I am sure that number 1 reason is the primary driver for ACBL tourneys. But on BBO, playing only a few of the opps in your directions makes it almost meaningless to have a section unless the sections consisted of only the number of pairs that you have rounds, but that would limit you to one winner per secction, so it comes back to the only real fair way is to matchpoint and assign points across all sections and all pairs.