MU
I would think Ciani had other work commitments in the Autumn, much like Michael Hurll did with the Late Late Breakfast Show in the 80s - IIRC Brian Whitehouse produced some or most of the Autumn 1981, 82, and 83 shows, and also did a few in 84 alongside Appel. By the end of 85 they were likely producing more shows than Hurll was, although he would still receive an Executive Producer credit most of the time.
Top of the Pops
Stan Appel's produced and directed the last few episodes, Paul Ciani stopped producing every year from around August or September until the end of the year while he was in charge for whatever reason.
I would think Ciani had other work commitments in the Autumn, much like Michael Hurll did with the Late Late Breakfast Show in the 80s - IIRC Brian Whitehouse produced some or most of the Autumn 1981, 82, and 83 shows, and also did a few in 84 alongside Appel. By the end of 85 they were likely producing more shows than Hurll was, although he would still receive an Executive Producer credit most of the time.