I work in the service industry, and there is posibly a way to add one additional person depending on their table configuration...lets say they have to use 3 tables of four to make a reservation for 9 people, or even 2 tables of 4 and 1 , 2 top you can easily squeeze an extra person in. So I would cal MS and see if it is possible to add just one extra person to you table,
Most table configurations allow for an even number of people, so 9 or 10 people would require the same number of tables. just my 2 cents worth