I think if you shoot fixed broadheads you'll need to use those to sight in--there will probably be a difference between your field points and the fixed broadhead.
If you use mechanicals, not so much. I use NAP Spitfires 125-grain and I discovered early on in the process that they shot the same as the field points, so I only use the field points to sight in now and save my mechanical heads for the field. I'd assume this is the case for most mechanicals, but I'd prove it to myself first.