One thing you didn't mention (if you did I missed it).. Has the state of aquatic vegetation shifted any???
Pretty sure a 15" LMB would consume a 4" TP, maybe even a 5".
My personal opinion is that you have strong natural predators. Every year will be different in growth and numbers as well as the type and amount of aquatic veggies. TP can change the algal structure which can affect other species as well.
My 2 cents... sounds like a well balanced system to me.
