I went to Hungry Jacks and found that now they only fill up to the second to the top rim of the Cup. Confirmed with the Manager on duty that this wasn't a mistake.
When I got home, I measured it out with a Pyrex measuring cup and the previous minimum was 600ml and now it is 400ml.
Pay for a "Large" cup but don't get filled to a large size! It only looks like a little bit but it's actually a lot because the cup is tapered.
For comparison:
7-eleven: Fill up as much as you can fit (including dome), they have even supplied bigger cups for re-use at various times.
McDonalds: Always to the very top or close to.
KFC: Always to the 1st from the top rim.
Coles Express: Fill up as much as you fit (including dome).
Been happening for years: http://business.time.com/2011/01/13/seattle-stadium-beer-sca…
Yeah the 'small' one doesn't get filled to the brim like that, but the difference is minor.