For the application metering report
https://docs.daml.com/app-dev/grpc/proto-docs.html#applicationmeteringreport
Is there any specification on event? e.g. if one exercise command results in 10 new contracts created and 5 achieved. How many events it records. if one choice invokes another choice, how many events it is?
The documentation lists the different events. It matches the transaction nodes you see in Daml Studio (the transaction tree service does not include fetches & lookups so it wouldn’t exactly match).
For your example, you get 1 event for the root exercise, 10 for the creates & 5 for the consuming exercises that archive the contracts so 16 in total.
Small clarification: I’m assuming that the exercise at the root is separate from the 5 archivals. If that causes one of the archivals (by being consuming), you only get to 15.