2K26 Play now online - What's the deal with the team tiers?

I got all I wanted from myCareer and myTeam, so I moved to Play now, and enjoy the balance of games. But I don't get the tier system, particularly for historic teams. Like 02-03 Spurs and Mavericks are tier 3 and they are really good teams. But there are some stinkers in Tier 1 like the 02-03 Bulls and I don't know how the 91-92 Magic are Tier 2, that's one of the worst teams I've played with.