League leaders doesn't increase merchandise. Last week I lost both my league games, won my cup game and one of my players went from not in top 10 of points to leading the league in scoring with 2 50+ point games ..... my merchandise dropped 5 k ;) So I think winning league games is the most important part of generating merchandise dollars.
The part in bold is the only relevant part of your post. You can't expect merch to increase if you're on a losing streak. I'm assuming your fan survey is stellar right now?
On the other hand, if you went 1-1 over those games (winning the one most recent prior to the econ update) and a player came from out of nowhere to lead the league in scoring during that period, you'd have a much better idea of whether the leaderboard had anything to do with merchandise.