I asked the same type of question, after I read the new rule. Here's how I understand the answer I received. Under 280 fps,grainsdoesn't matter. If you declare bow weight then use the 5 grain rule. This is how I understand the 2 lbs. variance. On your scale at home, your bowpulls 65 lbs = 325 grain arrow, 2 pound variance means bow pulls 67 lbs on shoot scale, arrow weights 325 still ok. Bow pulls 67 pounds on shoot scale arrow weights 324 grains = DQ'd.