Originally Posted by
weasil
The fact that you didn’t understand such a normal clearance...
To to be clear though, the way that clearance was issued is a normal procedure in the USA and it means climb via until reaching 15000 and then stop climbing.
Hope that helps.
You’re missing the point. Your last paragraph is what the original poster also understood from the clearance. However, the controller wanted him to keep climbing to FL230. That’s why he had to ask for clarification to begin with.