As of August 2nd there is now a processing fee of $0.99 per track for both original and cover song tracks.
You are required by law to notify copyright holders when you are distributing their composition in a fixed format (e.g. a sound recording).
Streaming services currently pay the royalties while download services require mechanical licenses (i.e. $0.091 per download) paid by the "seller" (i.e. artist), but in every case the cover song needs to be cleared with the publisher of the composition.
Our system also does not have a mechanism to separate streaming and download deliveries so unfortunately even if you choose only streaming partners you will still need to pay the $.99 licensing fee per composition.
Keep in mind that this is a one-time administrative fee which makes sure that the song is cleared for licensing on any site.