I run across many officials with this same thought. Many are under the impression that signaling the "attempt" is just that, but that signal also indicates that you have the shooter up & down (one foot). So in a 2 person game if both officials have the attempt, who's watching off-ball where 70 - 80% of the action takes place?
Even in a 3 person game, when 2 official are signaling the attempt, someone should recognize that, drop their hand & officiate elsewhere.