The store expander sends your release out via a so-called aggregator in addition to our direct deal. An aggregator is a very big distributor that usually exclusively works with distributors and big labels.
This allows us to reach significantly more stores than we could with our own deals alone but the aggregator takes 10% of the revenue earned via the store expander. If we see a lot of streams/purchases coming from a store covered by the store expander we'll try to get an own deal with said store but 90% of revenue from those stores is still better than none.