The thing is... GTWS doesn't have "splits". It used to have an actual "top split", called the "Superstars Race", but there is no official seeding of brackets. The "split" terminology is something used by players to refer to the effects of matchmaking, but it doesn't actually exist.
GT7's matchmaking simply groups players by SR, then puts the top 16 DR together, then the next 16, then the next 16, and so on. This creates the idea of a "top split" - the top 16 SR90-99 players by DR - but it's not something that's actually regulated.
Given that splits don't exist, this idea that points are stepped down in each split is also moot. The points are exclusively based on the average (mean) DR for that lobby, and it's something in the region of 2% of the mean DR as the total points pool with around 10% of that going to the winner and each subsequent position scoring 0.5% less.
Thus you can see that if everyone in a lobby has 100,000pt, the total pool is 5,000pt. The winner gets 500pt, second gets 475pt, third gets 450pt, and so on. It's actually a little less than that, but for napkin calculation purposes that'll suffice.
Importantly you can also see that once the top dozen players have done their three rounds and got the points they want, they can tank their DR or just boycott the remaining races to take their DR out of consideration for points calculations. If the top 16 players only have an average of 90,000pt, the points pool drops to 4,500pt, and there's now only 450pt for the winner.
That's actually the issue with GTWS Nations as it stands: drivers getting points for themselves and then limiting the points available to others, not this "I finished P9 in 'top split' but I'm behind players who won their 'second split' races" idea. There's actually no reason why a 'second split' race can't be exactly as difficult as a 'top split' race, and I think you'd probably find that the pace required to win a 'second split' race is within a couple of hundredths of a second a lap of the pace required to win a 'top split' race.
The solution for that is to stop dropping rounds, and/or to mandate a minimum of 75% attendance (for GT1; others don't matter in terms of GTWS qualification).
GTWS's real issue with points isn't that, but the converted leaderboard points for Manufacturers Cup.
In essence, at the end of each round the best single race points score for each manufacturer in each region is taken (with the rest ignored), ranked, and converted into a new number. The best manufacturer score in any round in a region is converted to 40pt. Second best is converted to 36pt. Third best is converted to 33pt, and so on down to 1pt for 25th (26/27th score 0).
Those scores from each of the three regions are then added up to create the manufacturer ranking, obviously with a maximum of 120pt from each round.
Not only is that a bit convoluted and tricky to follow, it has the exact same consequences: a manufacturer could theoretically qualify for the world finals top ten based on a bunch of 400pt finishes in poorly attended rounds, while others need 450pt+ finishes in better-attended rounds.
Worse, it could do so from the finishes in two regions and drag a third driver who is unsuitable for WF events (like me!) by virtue of them being the best finisher in their region for that brand but 1-2% off the pace. We have seen it in the past, and I think those drivers who have qualified in that manner are cognisant of the fact they're outgunned - but it's hardly their fault.
