Thank you. The Seats Available option definitely adds the line with the number of unsold seats/seats available, but checking the Available Seats Button did not add a button or do anything else.
the 10.5 section of the current help document does not clarify anything that I can make sense out of:
10.5 Shopping Trolley and Box-Office Customisation
A number of customisations to the Box Office and Shopping Trolley are possible,
either by changing values in the Settings, or by the addition of defines in the
StageShow site configuration file (stageshow-wp-config.php).
any further thoughts would be appreciated!