I kinda expected that. Sadly stats/salary is a poor indicator of actual cost efficiency. It's like that one time where this guy from a bot laden div II asking me to call up his barely trained 21 year old SG because "I need a player who can perform off the bat" and his player was leading the league in points. The reason I didn't call him up was because his skill levels were just equivalent to a 5 ball 19 year old draftee. Wouldn't even make the bench for the U21.
Cost efficiency actually means being able to squeeze in as many TSP as you can and still keep the salary low. You can't use stats as a measure because it is affected by a lot of other external factors: defenders it face, game shape etc. If your player has 1 good season and 1 bad season after that, does that mean it turned from a very cost efficient player to a one with low cost efficiency? That's why we don't measure it with stats.