If I'm not mistaken I think they continued working with Moroder up until 1981. The album that followed "No. 1 in Heaven" (Terminal Jive) has been cited by the bros as their least favourite. (Which makes me wonder why they cut a third record with him.) According to the story, they didn't have a lot of creative input because Moroder had other plans in mind (and took over so much of everything that went into it). It still sort of sounds like a Sparks album, but it's nowhere near as incredible as "No. 1 in Heaven".

Terminal Jive is an album I like to play now and again and always think THIS TIME I'm really going to enjoy it, but usually end up disappointed. Whats so startling about this album is that the songs are there but the whole thing sounds like a flat can of Coca-Cola, which is really disappointing considering how vibrant, exciting and fresh No.1 in Heaven was. Also the black and white album cover gives out a subdued feel as well. After this album Mack took over on behalf of Moroder and I really love those next couple of albums.