Currently in STM (5.7) there are port error statistics interpreted per switch only - one error counter value for the whole FC Switch.
So also the Threshold and Alert settings are only possible on Switch Level.
It would be more useful to have port error statistics per port for easier troubleshooting and granularity in alerting.
If I get an alert for a certain port, it is lot more easy to identify the root cause as if I have to investigate further on the Switch where these errors are raising...