We have often wondered about the difference between the way we compost and the many companies who sell bulk vermicompost. Most, in the USA, are motivated by the need to get rid of a "single source" of waste, such as certain manures. Even the first large vermiculture operation I ever saw was devoted to getting rid of coffee hulls, in Costa Rica.
It was our original intention to develop a way for the typical household to get rid of their organic wastes of all kinds instead of sending them to a landfill. That usually includes a "broad-spectrum" of wastes such as grass clippings, shredded leaves, coffee grounds, kitchen wastes, animal manures, etc. (Not from domestic pets, however, and no meat or dairy wastes that putrefy before decomposing entirely)
Vermicomposts are analyzed in two ways; quantitative and qualitative.
A quantitative analysis is about density. It counts the number of microorganisms in your vermicompost. It doesn't matter if there is only one kind (highly unlikely) but only the number of the total. It seems logical to think that if your compost and vermicompost come from only one source, like coffee hulls, for example, you will have a large number of only a few kinds of microorganisms.
A qualitative analysis is about diversity. It counts not only the number, but the variety of microorganisms in your vermicompost. If you have a "broad-spectrum" of organic wastes in your feedstock, it would seem likely that you will also have a wide variety of microorganisms in your end product.
Some composters insist that you need to add some dirt to your compost to provide a "starter" of microorganisms of all species, but we think that unless you are washing off your leaves, etc. first you are getting lots of dirt when you gather your stuff. If you feel it is important, go ahead, but a little is enough.
We believe that there is much in Nature that we don't understand. We know for sure that N-P-K is the tip of the fertilizer iceberg, and we believe that there are things produced for plants by microorganisms that haven't gotten very much publicity, yet. We prefer to think that the more diversity in our feedstock the better.