To this discussion I'd add that singles, now matter what format were all based on one song, sometimes two, which the band/record company wanted to promote.
In The Beatles days, the original UK albums didn't feature many of the singles ("She Loves You" and "I Want To Hold Your Hand,") though they were usually recorded during those sessions. Singles got on the radio, making bands popular and albums were an entirely different entity.
Then the album as a work of art unto itself began to take more prominence in the late '60s (Rubber Soul, The Beach Boy's 'Pet Sounds,' Sgt. Pepper, etc.) By the '70s, singles usually were songs from an album, played on the radio to promote the album and band (who were often touring). Also, by this time, E.P.s were becoming a rarely used method of releasing songs, as you tended to only need the album and its regular single. "Regular" would be two songs. The A side was the potential hit and the B-side was either and a middling album track or (if fans were lucky) a non-album track.
(There are exceptions to everything and sometimes B-sides tied or beat out the A-side in popularity: "We Will Rock You" was a B-side in most territories, as was Rod Stewart's "Maggie May").
So, though artists still call singles "E.P."s on occassion, they're a mass-market rarity most of the time. By the dawn of CDs, two songs on a single wasn't ussually enough. Three or four became the rule. You still had your "hit" song leading it off and either album or non-album tracks, but just as likely you'd get some other rarity (BBC take, demo or remix).
Star Fleet Project wasn't an E.P. because it wasn't promoting an accompanying album and was too lengthy in original material to be a stand-alone single (like Freddie's "The Great Pretender" single, which had no album in 1987). As someone said in a previous post, they split the difference and made up "Mini-LP" (Mini Long Play album).
The amount of original material, in my opinion, is a key to understanding the semantics of calling a release a single, E.P. or album (or mini-album). An hour-long CD of five remixes of a single track has little original material on it, so "You Don't Fool Me" Remix singles of the '90s aren't even E.P.s (Extended Play singles). It's not about sheer length.