No Scoop? No Problem! indicates the Huel scoop is 1/4 cup. According to that post and the nutrition facts 1 cup is 500 calories making 1 scoops equal to 125 calories.
The "Let's Get Started..." booklet that arrived with my order indicates that 1 scoop is 150 calories.
This has left me really uncertain how to measure calories of Huel. depending on which numbers are correct an expected 450 calories could be 375 calories or an expected 500 calories could be 600 calories.