Straightarrow

I don't know what the outfitter's reasoning is, but I've always gotten better fixed blade broadhead flight when increasing F.O.C., as long as the arrow had adequate spine to handle the extra weight. Also, in some broadhead designs, the extra weight does make for a more durable head. Whether this will be of any benefit, will depend on the individual's set-up. It could be this guide thinks the benefits of a 125 gr head outweigh the possiblity of someone showing up with a 75 grain head on a light arrrow with an F.O.C. of 4% or something like that.

It would seem wise to me, to ask some questions and have some flexibility on the head, depending on the person's setup.