If you consider yourself detailed and don't own a digital food scale. Invest in one. Not just for your food but also for your supplements. Protein powders are a bad one for the "serving scoops".
There are way to many variables with this and a lot of companies put a over sized scoop with a serving line on it knowing we just scoop and dump what the scoop holds.
This does 2 things. Over serving dose and makes you go threw more of the product.
Whats a level scoop? Level to the top or the line?
Whats a heaping scoop?
Whats a rounded scoop?
Start weighting your liquid and powdered sups and see how much longer they last.