My guess is whoever replaced the prop just got some bad advice, and the pitch decision was based on a table lookup from the seller. Perhaps it was replaced due to damage or electrolysis.

Two-blade is more efficient, in some designs (although it has more "slippage") so you can't go strictly by that.

If it were me, given that it's a production boat I'd look at whatever works best for sister boats and go with that. (BTW I'd also go with folding or feathering, given that it's a sailboat.)