Jon,
To me anyways, I'd question the adjustments you made by going lighter spined with a lighter tip. Obviously good form is something everyone should strive for, but I bet your a spine or point weight is off. Some bows are picky, others you can get away with a wider range, is what it is. Really from fur to spruce you're not going to change your FOC much without doing some serious spine changes either up or down. It would depend on how much you wanted to lighten the point weight obviously.
A simple test is to find some points heavier and lighter and run them, see how they fly. That will quickly tell you if they are too stiff or too weak without doing anything drastic.
a word of caution on spine testers, they are not always calibrated equally. Though you may be on with yours you might be 3lbs off the makers numbers. I had this issue with a well known POC maker before they retired. Once I knew it I could adjust accordingly, but that ment testing my own shafts. Check your calibration against aluminums deflection (done on a wood arrow spine tester). You can find charts on line for this purpose.
Orion,
I've had this discussion with a wood shaft maker years ago now a few different times. Initially I assumed the same thing, but after some testing, it confirmed what he was saying I needed to go up on the lighter arrows held true at least in my case. Mind you this was out of a recurve that was very tolerant of spine selection and I haven't bothered to retest that theory since. He is now moved on to other things and the way things are going I'm not far behind him.