I wanted to post the exact same question and found this!
Anyway, my observation is this: Say you have a shop with 3 level 9 dream jobbers, you will NOT get any bux by making one of these level 9 dream jobbers jobless, and replacing with another dream jobber because level 9 is already the highest.
However, you can get a bux if you have TWO or more extra dream jobbers for the same shop. For easy explaining, let's call the 3 original level 9 dream jobbers A, B and C. And you have another 2, X and Y, with skill level 4 and 7 respectively. Suppose you free up a slot by making anyone of A,B or C jobless and swap in either X or Y.
You will never get any bux from swapping in X or Y because both their skills are lower than 9. But the KEY point here is the sequence in which you swap them in.
Sequence 1: If you swap in X (4) first, of course you won't get any bux. But after you evict X and swap in Y (7), you WILL get bux for Y because Y's skill is higher than X's. Of course, you won't get any bux from swapping back the original level 9 dream jobber.
Sequence 2: Swap Y in first - you won't get any bux. And you also won't get any bux when you evict Y and swap X in because X's skill is lower than Y's.
In the same logic, if your shop only has 1 or 2 workers originally, you will get bux from the bitizen who fills up the vacancies at the shop. But once you get a level 9 in, you'll have to use the above method.
I read somewhere that you could intentionally leave a shop empty for a while, and then to swap in the extra dream jobbers to get bux (while your level 9 dream jobbers are hiding elsewhere) but I'm not sure if this method does work. Anyone who has successfully gotten bux this way (in this paragraph) please do let us know.
Best Answer
Probably the game has some tiny lag moment and the game doesn't detect your finger anymore therefore "deciding" to stop at that level. You only need a few miliseconds to stop the elevator and the character will step out right away. Perhaps this explains your issue.