The first throw with almost any powder (unless the weights are 4.0gn or less, in which case my machine doesn't really get out of trickle mode) will be about 1.0 over as it over-shoots. Every throw after that is x.x +0.1/-0.0gn--even Trail Boss.
First, CALL RCBS. Guess what? There is a problem with your machine. First, get that fixed and then learn to program, if needed--but I haven't and I have one of the first ChargeMasters made. In fact, McD straws don't fit my machine at all and I have never needed it (but I tried any way)--I can only assume that RCBS switched to a larger OD/ID tube at some point.
If it overshoots by 0.1-0.2gn, it really doesn't matter. If you can't stand it, simply lightly wet a finger and pick up a couple of kernels of powder on your finger to get the "correct" weight. Then, look at your finger and see how small that amount really is.
People worry about slightly over-shooting the max load in a manual when, if you check several manuals, there is a range of max loads depending on components and lot numbers used (so your manual's max load could be over max or under max in your gun with your specific components and COL). These same folks are quite happy to load +P and +P+ loads or even 9mm Major...
I remember when the approved method to reload for a bolt action gun (there were bolt action pistols) was to increase the charge until the bolt was hard to lift or there were extractor marks on the case head or the case head expanded and then back down 0.5-1.0gn. Some folks were shooting 85ksi pet loads all the time.
Don't try this at home.