Statement from 7-Eleven, regarding coffee cup sizes.
The milk foam in any latte or cappuccino purchased from any café will naturally settle over time, or be ‘flattened’ by repouring into another cup.
7-Eleven’s freshly ground coffee is outstanding value for customers and the simple $1, $2, $3 price points are based around industry standard cup sizes. Depending on the product the customer selects, there are different ratios of coffee, hot milk, and milk foam (proportionately more for each cup size), and of course the foam does settle over time, or when being re-poured as in this example.
One of the reasons we introduced other sizes is because our customers told us they wanted the convenience of a range of sizes to choose from. But customers are welcome to super-size the value they get from our coffee by purchasing 3 $1 coffees instead of the $3 size.
It appears that a foamy style of coffee, such as a latte or cappuccino, was used in the video. Therefore the reduction in the air in the milk foam, which occurs naturally over time, and in this case also by repouring it into another cup, would result in the overall volume being somewhat less than when it was originally poured (as well as missing the foam that remains stuck inside the original cup).
If you try to fill a $2 cup with a $3 serve direct from the machine, it will overflow.