There's no valid reason imho to reduce flap.
You should really try and do what the POH says. I don't have a PA-28 POH to hand but my Cessna one recommends less flap in gusty conditions. I suppose there is more risk of ballooning(?), just a guess. I've also heard the reason is that there is more chance of a go-around in gusty conditions and that is safer with less flap, again I don't know how true this is. Using less flap works for me.
Have a look at the PA-28 POH and see what that says.