The longer boil times increases Maillard reactions. This will create very specific flavors and characteristics required for many of those recipes (Especially the Scotch ales). I typically like to boil longer than normal (90-120 minutes). It gives a maltier and more rich character.
Although, there are many styles and recipes that don't work well with this method. If they say to do this, then do it.
Not sure about the invert sugars, but a quick search of Homebrewtalk gives some good results:
There are plenty more if you do a search.
"There is no strong beer, only weak men"
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"Give a man a beer, he'll drink for a day. Teach a man to brew, he'll be drunk for the rest of his life."
Primary: Hoppy Wheat, Porter
Kegged: Reaper's English Mild (OO), BBK Jr., Lagunitas IPA, Fireman's #4
Notable Empties: Oaked Black IIPA, BBK I, Red IIPA, Burning Bush, Apophis "The Destroyer", Vanilla Porter
On-Deck: The Titan BW, Ale of Olympus