Part of the problem is manual time keeping. You're almost better off using a different approach... But finding a mob that you can sit there and shoot into for an extended period of time is hard. Additionally, using weapons that are already very fast puts you at risk of rounding errors.
I know Manual time keeping isn't 100% accurate. But that's why I took data from 10 timed shots and averaged them, and thats why I showed that with no buffs I tested the Reaver and got 2.1 sec. This is not the point of the test, it was to show that somethinig is not stacking and I found it.
And if Manual Time keeping is so bad how in the heck did I get the exact same RoF for SET UP #2, #3, #7?