I believe Warner's just dumped Twice Upon a Time and didn't give it a proper theatrical release. (A fate that befell a couple other non Disney animated films that decade.) Aside from a Los Angeles screening for which I got a mailed invitation from the original SW/LFL fan club, I don't think it ever played anywhere else.
IIRC, none of the other Ladd Company produced films Warner's distributed at the time were big hits, save for the first Police Academy. :/