Incorrect data in USER_STATISTICS

Looking at the output from SHOW USER_STATISTICS or SELECT from i_s USER_STATISTICS there are several values that seems wrong. In the example I have a user "statsbug" with access only to a database only. To begin with, it seems that you need PROCESS privilege to view USER_STATISTICS at all, but this is likely documentation issue. The problem is that you don't get an error, you get an empty result set.

Then we have:
COMMIT_TRANSACTION:
Should increment by a COMMIT but it is not, rather it seems to increment for any command and often with 2. A simple single row INSERT seems to increment it by 2 at least and if it is inside a transaction, it still increments by 2 even if a COMMIT hasn't been issued. The COMMIT increments it by 2 also.

UPDATE_COMMANDS:
This is incremented for both UPDATE, DELETE and INSERT commands. Again, this might be a docs issue.

ROLLBACK_COMMANDS:
This increments by a single failed operation, i.e. an INSERT with a PK error will increment this. An explicit ROLLBACK seems to increment it by 2.

CONCURRENT_CONNECTIONS:
Seems not to be incremented at all, at least in my simple tests.