For one, there seems a distinction to be made between "publishing" prices and individually receiving a quote in advance of work. If there's a technical sense in which the two are equivalent, I would recommend clarifying in casual conversation.

Those requirements also don't seem (though I could've missed something) to be a part of anti-trust law, per se. The requirement that prices be consistent is, in the cited Robinson-Patman Act (although that seems to only apply if you're crossing state lines?)