The point of bowling on these patterns is that they are difficult. But, IMO, they do not make you a better bowler. The experience will let you know what you need to work on i.e. speed control, consistent hand release, foot work consistency etc......., if you know how to interpret those differences in your game already. But the league will not tell you which problem you should tackle first or if you are actually improving on one skill and not getting worse on another.
Leagues like this (Sport and PBA Experience) are illustrators. They show you that you are not as accurate or consistent as you think. But they do not infuse you with the ability to deal
with those inconsistencies. The best experience I have had along these lines was a two day clinic I went to where we also had CATs analysis. We had 6 different sport coniditions to bowl on and over a dozen certified coaches to help you adjust and manage the conditions. A toutored Sport experience that was much more educational then when I played a Sport league. When I bowled a Sport league I was also bowling in two house leagues. My average dropped in every league I was currently bowling in. After the fact I found that this was common. Depending on your personality, this can really get into your head. At the time I did it, I did not have as strong a mental game then as I do now. And I still need to work on that. But I've also participated in a wider variety of bowling situations since then.
I also think that that the higher average you are, the more you have a tendancy to average lower on these conditions.