Just a theory... Are you playing on mobile? Is it possible the mobile browsers ticker has a max speed limiting the production, but the avg sold measurement is measured using an actual sold per second avg.
On my mobile the production seems to cap out at around 10/sec even when it reports far higher than that.
I consistently make ~3x as much clips as I sell "on average" and it still always trends down (e.g. if I build up a few k of stock, it trends downwards to 0 and stays there). If that's randomness, the data is presented quite badly.
On my mobile the production seems to cap out at around 10/sec even when it reports far higher than that.