No I'm not with you there Puggy, if you pour a cup full of Sangria and a cup full of Milk then poured each in to the others container then it would be the same.
However here we are pouring the Sangria into the Milk first, so providing some blending occurs when you re-pour a cup from the (now) Mangria you will then be returning a fluid which has to some extent a Milk content to the Sangria.
Now for the result to be the same then the cup you take from the Mangria must contain 50% Sangria, however if (for the purpose of this question) the Sangria blended completely with the Milk then what you have in your cup is 9 parts of Milk to 1 part of Sangria.
Therefore at the end of the little experiment there must in fact be more Sangria in the Milk than vice-versa.
I think
Ken