Clever !

I was thinking of something like a sugar dispenseur (turn the container to fill a volume, and this volume becomes you serving), but your solution is way more economical and space efficient.

Can't say it's mine, I've seen it on a rice package!

I myself thought of a solution similar to yours, or even more complex solutions like revolving doors or having an internal chamber the size of a serving with two lids that can't be both open at the same time..

But to be honest, I don't think any of this is really useful beyond a restaurant where sizes are fixed (and indeed use pasta-specific ladles to have standard portions). Depending on the day of the week or how many and who's at home I'm still better doing the math with a scale than predefined servings.