[FACT CHECK]: Milk costs 4 pints £1, aka, cheap. Coffee bean is 10x more expensive. Coffee machines take similar amount for a cup. Simple maths, if one thinks bigger cup (or bowl) gives better value for money. This is WRONG !
Nowsaday serious coffee shops gives smaller cup, but better coffee beans. Consider that good coffee beans is much more expensive, easily 3-5 times more than commercial beans (which most cafe used). We are talking about quality, not quantity.
MYSTERY SOLVED !
We use standard cup size (being a coffee trainer, we always use standard). All machines take ~same amount of coffee. A bigger cup cannot give you "more" coffee, just more milk, or more water. If one really needs more milk, just ask. We give more milk up to what he/she would like.