i work at a pool hall, and if that person is well known there he may just pay a straight rate of 7-10 bucks for the night, thats what we do at our hall, if you come alot, are on a team out of there, or are a friend of an employee its $9 for the night and $5 if you are an employee and on certain nights its $7 for the night...the sad thing about the 7 bucks is that people come in and complain to no end and ill end up putting them on table time and when they leave they pay at least twice what it would have been, thats if they stay more than an hour or 2.. but i think that at a normal rate of 6 an hour for a single person and 3-4 bucks per person when there is 2 or more that 7 dollars is a good deal. Idk thats just me, before i started working there, I would hold off and wait for the 3 nights that it was the 7 dollar deal, and then you get the people that just walk past the counter and go to a table that is already taken on a busy night and pull out some quarters and look for the coin insert, to their dismay when i walk up and say you need to get your own table, if there is one open, you have to pay 7 dollars. the answer is usually "well i just want to play a game" i reply ok ill put you on table time then, and it ends up being 2 hours later and over the 7 bucks.
back to the topic, if he was well known or if he is a hard hitter of some sort he may have a flat rate, but if not, i dont see why you cannot just go to the computer and just enter 2 instead of 1, but with our computers, if someone plays for an hour on table time and someone joins, there is no way to differentiate the hour the first person played, it will just tell you the total for the both of you. It will show how long player 1 and 2 were on if they came in separately but the point is, its an annoyance to add someone to a table if another has been on it for awhile. just my view point as an employee at a pool hall.