boil times with late extract additions

I've noticed more extract or partial mash recipes that specify adding the malt extract (liquid or dry) either in the last 10 minutes of the boil or after flameout. Many of the recipes also have less than 1 hr boils. These include recipes posted by White Labs. The obvious benefit is reduced caramelization and lighter color. Has anyone tried a few brews with late extract additions (compared to early additions)? If so, here are my questions: 1) did hop utilization change noticeably with the lighter boil gravity? 2) Is that possibly why many of the recipes are 30 to 45 min boils rather than 1hr boils? 3) did you still see a benefit from irish moss? 4) any hidden benefits or problems with the late malt addition? I'm thinking about trying it on a wheat beer tonight. I would like to lighten up my brews and get rid of the "house flavor" where I can, but I don't want to trade for an unexpected shift in bitterness at the same time. THANKS! Jonathan