The producers make the decisions about all aspects of ticketing for a show. The box office just follows the rules set forth by management and if you get annoyed, get annoyed with the people who are presenting the show. Chances are if you're annoyed, you'll act it out with the box office which will probably get you little accomodation or consideration.
You'll accomplish nothing by being haughty, rude or nasty with the box office. Be honest and straight-forward by presenting your discount coupon ahead of time, be clear about what you want rather than rejecting every 'good seat' without saying 'but I really need to be on the aisle' and don't treat the box office like they're idiots. A little pleasantness goes a long way.
There's an old saying in the business that goes 'anyone who fights with a box office person has only one problem: they're nothing getting...'
You can surmise the rest.
The number of people who will not see a show they don't want to see... is unlimited.
Oscar Hammerstein