Having done sediment test for some years, I can tell you things, at least with respect to Delta clays and ADA AS, which are similar and water column doisng based on that analysis.
You will not run out of nutrients in the sediment(for those listed above), for most of the nutrients other than Nitrogen.
If you dose the water column, then there's less demand from the sediments, so they will lats longer. Common sense asks why not use both locations?
Once you add sediment rich nutrients, then they are there and no further work is really required from then on. That hedges against any errors and forgetfulness regarding the water column. the water column dosing is more flexible and you prevent the sediment from running out of certain nutrients and can dose more KNO3 later.
So now you have two locations for nutrients, both short and long term supplies. These 2 locations work together, not opposed. I'm not sure why some suggets to dose only the water column and then others that do not suggest to dose the water column using soils etc.
These are very counter productive suggestions/ideas that make the methods worse, not better.
Soil folks still need to dose some things, so a couple of N and P dosing will not add any horrid burden upon them. Likewise, water column folks are not out that much for adding some soil/clays etc, and then once done, they are set for years, they can leave for vacation and come back without having dosed all week and things look great. Maybe you want to run the water column leaner but do not want to bottom things out too much, sediment will offer a back up safety net.
Given a choice, which we do have, both makes the most sense and logic.
Then you can focus on larger things, like light and CO2 issues.