too mild camshaft

Cracked back, you are not geting the point....at the valve LIFT increases.
How much lift at a particular duration changes because you have more lift at the valve at the same duration measurement. You don't measure duration at the valve. Duration is measured in degrees. Valve lift is measured in inches. The numbers do correspond but not in the way it has been described.
the whole purpose of "advertised" and "at .050" lift" numbers is to give you an idea of how aggressive the lobe is. There are plenty of cams out there that have seemingly identical lobes when you compare the advertised duration, but the at .050" number tells the rest of the story. this is why you have cams designed for less endowed engines (smaller diameter lifters) and cams designed for big manly mopar lifters!

I don't know how else I can say it. A rocker arm can not and will not effect duration. It effects lift only. The at .050" measurement with the increased ratio rocker arm will widen the at .050" lift number in degrees ONLY because the valve is opened further, faster in relation to cam rotation. It has no effect on overall duration.

Check out this chart...you will notice that they don't even list the change at .050" lift duration, only lift, when comparing different rocker ratios on the effect of lift at the valve. The at .050" change is not worth measuring because it is inconsequential.....unless you are straining the limits of lifter diameter.
http://www.oregoncamshaft.com/Hydraulic-Cam-Specs.html