Self compaction zone? What is that?
I think Mr. Sottilo needs to do some reading about how soils function, then design a controlled experiment to test his hypothesis.
Adding a layer of compost over top of a sand-based rootzone certainly could create a layer of textural discontinuity at the interface of the sand and the compost. But, this is not compaction. Remember, compaction is the result of an increase in soil bulk density. Were bulk density measurements taken? if not, he can't say anything about compaction.
I would also challenge his assertion that merely applying compost tea over top of the compost topdressing application caused the existing rootzone and the topdressing to intermix below the soil surface. One of the first things we learn in Intro to Soil Science is the difference between soil physical properties and soil chemical properties. This seems to be lost on Mr. Sottilo.
If there is some scientific study that has been conducted, I would be interested in reading it. But, I have no use for anecdotes and a poor use of terminology.