I believe his whole point is there's no need to boil the second half because it has already gone through the process before it was transformed into a liquid malt.
I do "late boils" as they are called and actually get a second hot break.
I boil about 1-1.5 gal of water with 1-2 lbs of malt (1 grain and 1 extra light DME) for 45 mins. This keeps scorching (carmelization) down to a minimum which keeps the color of the brew lighter.
I do not get clumps from DME because I turn the heat off and add only 1 lb at a time, stir it in, then add a second or third, etc. The trick is to stir it in and let it dissolve before adding the next lb then boil for another 15 mins. The hot break happens sometimes within 2 mins of the re-boil.
