Have your tested them with a fixed blade broadhead yet?
I can shoot under spined arrows pretty well with light point weight. But when I load them up for hunting and improved FOC with heavier broadheads I can not tune them even close to my FP. I'd say from MHO the charts are right. Plus for a safety factor I'd be checking those shafts for hairline cracks all the time.
Just my .02 on this and for me a stiffer, heavier shafts does a better job keeping my bow quiet and accurate.
Someone demonstrated to me with a spine tester a couple of years ago now that some carbon and AL shafts are not as stiff as they are advertised rated. Another reason to stay on the stiffer side when selecting an arrow.