While there is a Moccamaster that uses the right bottom switch for different brew sizes, the one you had wasn’t it. That button controls the hot plate temp on this particular model. For full liter, you use full open position on the brew basket, and for half liter, you use half open position. The closed position can be used for either a bloom, of to get a cup before the filter basket has finished draining. It’s really very confusing, but makes such a good cup of coffee, it’s worth the effort!
When you say cups is it 250ml (8oz) or 150ml (5oz)? I assume it's 250ml (8oz) since recipe card says 1L. I have a Sage, aka Breville, precision brewer, and 1 cup is 150ml (5oz).