My guess is that you lip-read?....fluently?...or ur boss would have not put you in that position to deal with hearing customers?....
As for the "sign", no, I would not....as hearies tend to "talk over each other" at times. So ur deafness or ur being HOH is somewhat of an advantage here....One customer at a time....and the complaints they make, plus the profane language when they get angry!
Sounds like a frustrating job dealing with hearies in customer service since you are deaf....or ur HOH? and can "hear" customers talking and asking questions, argueing, etc.?
Not much info. here to make a judgment, tho'.