If you're looking at execution status, then you're correct. It is only an indication that the script ran to completion.
So if the script produced an error, say from a verify statement, how can this be shown in Central?
That would show up as a zero score for the Accuracy measure for that single run on the Health charts. It would be averaged in with the scores from other locations and with the scores for the aggregate time period.
Have a look at:
- Section named "Configuring Performance Ratings" in the Application Performance Monitoring Tutorial and also
- Section named "Analyzing Results" in the Central User Guide