to be honest and this is just my $.02
field tips and broad heads will give you different FOC
field tips fly through the air different that fixed or mech blades and over long distances will alter your arrow path
Don't shoot just field points and screw in a hunting head to go hunting, practice with the heads you intend to shoot. Know how they fly, and adjust to using them.
field tips are perfect for target shooting
broadheads are perfect for hunting
use and practice with what you plan to shoot at.