When certain styles of German beer are produced, usually, beer made with high amounts of high protein, high fiber Beta Glucan ingredients, hops are added into each decoction and boiled with the decoction. The hot break and mud that surfaces are removed from the boiling decoctions as they form. Boiling the mash and adding hops helps with lowering viscosity and lessens the chance of a stuck sparge. Boiling the mash cleans the wort and makes it stabile and chemically balanced which reduces the chance of off flavors forming during fermentation and conditioning. About half the amount of hops are used with the decoction method compared with the amount of hops used with other brewing methods because the wort is cleaner when it's made from the decoction method. Large amounts of high Alpha hops aren't needed to clean and overcome the chemically imbalanced, muddy wort that other brewing methods produce. Wort becomes chemically imbalance when it's in the boiler, boiling. The enzymes that change the newly formed chemicals into beneficial vitamins and nutrients are long gone by that time.
I'm not sure if hops add any significant value by adding them into malt soaking in hot water because the temperature is too low to cause chemical precipitation to occur that occurs when mash is boiled. For filtering, hops are awesome and if enough are added to mash containing a lot of goop, sparge would probably be easier.
First wort hops are added in a different way than brewers add them. Here's the way it's done. When the bottom of the wort boiler is covered with extract stop adding extract and fire the boiler. After the extract starts to boil add a small amount of hops or a handful of crushed black malt and very slowly add extract without stopping the boil. Skim off the hot break as the boiler fills. It's a trick from way back. Less worry about boil over and the boiler can be filled higher. Hops and black malt reduce surface tension and that's about all there is about first wort hops. They're used to improve the quality of wort. The focus isn't placed on the bittering aspect because the hops shouldn't have any impact on bittering or flavor. The hops added later on, do.
It's always a good idea to skim off the hot break as it forms in the boiler until it stops forming or drastically reduces before adding bittering hops. The wort is cleaner and less hops are needed because hop character sticks better to clean wort.
A few years ago I watched a brew guru recommend spraying starsan on hot break to get rid of it, spray wort with starsan before and after adding hops. It was hilarious to watch a brew guru do something like that. Perhaps, wort becomes cleaner when soap is added and even cleaner when beer is added into a fermenter containing starsan. LOLOLsssss!!
