How do I query the ALS to show current license usage?

Use the lsmon.exe to view the details of all usage. It can be found in the path C:\Program Files (x86)\AVEVA\AVEVA Licensing System\RMS\Tools folder. Create a .bat file in the same folder with the following lines in it:

cd C:\Program Files (x86)\AVEVA\AVEVA Licensing system\RMS\Tools

lsmon.exe yourservername >license-used.txt

Change yourservername to your server name and run the .bat file. It will create a file called license-used.txt with a snapshot of the keys in the license file and the clients accessing them.