Making a bow shorter to pick up weight can often be a case of chasing your tail. You can end up where you started, you just have a shorter bow. The limbs become more stressed and the bow takes on set. Net 0 gain. I have piked a bunch of them over the years, but prefer to plan in the length I want, and work from there. Flipping the tips can sometimes cause some of the same issues. I don't know the length, but I would say flip the tips before piking. If your real long, 70 inches for a 27 inch draw for example, then cutting a few inches off each end will still keep you long enough, 66 inches or there about. If you are already that short, then flip the tips in my opinion. Should up the weight a bit if your tiller is good. If not, then get it right first.
I will still come in light on some. Not by much and not often, but it still happens especially if there is a particular issue I am working around so don't beat yourself up over it. Identify WHY your coming in light, and modify your technique. For me, getting a string on it early is key. That first requires a good floor tiller so all is pretty even while bending 5 inches or so. Then check it with a long string moving the tips that same 5 inches while on the tiller stick. Get the limbs even with a straight edge at that distance. Now, get a shorter sting on it braced an inch or 2. Work the limbs moving an inch at a time. Get them bending right and even, and then shorten the string and increase the brace height to 3 inches or so. Keep taking baby steps until you have it braced 5 inches or so. Perfectly even at brace. You will be heavy at this point, so just start shedding pounds slowly while keeping the tiller even. Check the weight and see at what length you hit 50. 15 inches? 20 inches? Your good to go. Tiller has to be right from the moment you start flexing the limbs. The earlier the better off you will be. If it's near perfect once floor tillered (not likely), then your golden. If not then get that right before anything else happens.