They are just running numbers. If raising the cost of coffee by $1 brings more profit, then why not? And they can roll back if it doesn't work. People who are concerned by a $1 raise aren't particularly sticky anyway.
Because it turns out the manager just starts giving away the coffee for free, so whatever numbers somebody was pulling from the sales system were obviously incorrect.
The problem with "running numbers" like so many other metrics is that they are usually run by MBA types who have a weak grasp of math and don't really understand the customers' psychology (often work in corporate offices that are nowhere near the stores).
Dismissing this as "just running numbers" exemplifies management that has no idea who their customers are, their priorities, or why they choose that particular gas station over others nearby. It was rather obvious to the in-store clerks that the $1 coffee was a draw that often enabled another $5-10 in sales per visit, and since some of these people were daily customers, many of them contributed thousands annually. Try to get all of that back from an extra 1 dollar.