well how big the producer deems their next release to be wont matter much at all to an agency, they would want to see it sell very well and for the next few eps to do just as well to be convinced that your worth taking on. That coupled with great skills as a dj etc etc. There are all kinds of reasons how people get onto agencies, dont forget alot consist of tight knit groups of friends who probably arent even bringing it that many bookings, but are able to at least SAY they are an agency, if you get me? It's different with say the top agencies like Dynamix where their artists are all proven at what they do