JFR one thing to remember is the lower the lake level the less water it takes for it to rise. the fuller the lake gets the larger exponentially the lake is and thus it take more water to raise it in feet. ie the shorelines become bigger. So that is probably what you are seeing and why when the lake is at lower levels the lake rises greater amounts.
where I live, northern utah, we have saturated ground and giant snow pack to melt. a great recipe for runoff. however it looks like the eastern and northern parts of the colorado drainage while above average aren't as insane as where I live. I am not sure how much the western part of the colorado drainage will help provide the extra run off. Where I live, I hear you on the april to july run off numbers. But in years past with this kind of snow to melt our rivers will run higher and you will not see them become normal and reach their base flows until mid august. at that time generally no matter how much snow we got the rivers run about the same. but with this much snow we will see a much longer runoff period. its really too bad we didn't have at least an average year last year. If we did the lake would really be on the move,