Was the fact the bag she was talking about says 'Dunkin Donuts' on it, is what gave her away?
Say @Ebrahim11 you do have a most interesting price structure and in the long run may bring you grief, or not what you intended. You have 1-8 guests welcomed tom your place for $400 total, yet the 9th & 10th are charged $35 extra. Why not charge all along the way, meaning start say at $400 for the first couple (2) and jump by $25 every person after that. If 8 come that is $400 + $150 (6 x $25=$150) = $550.
In essence what you are presently appealing to a certain clientele at $400, which is probably a good one, BUT by rolling out a mat for 6 more guests to come for 'free' you are guaranteeing yourself to now appeal to a different clientele, meaning one only wanting to pay $50 per person on the average a day ($400 / 8). In fact the '$400 guest' that makes the reservation may not be able to afford that at all, may be a $50 a day wonder that knows he could get many of his cohorts to join. Hmm 8-10 people in that nice place of yours would get me nervous, which makes me think of the word 'party'.
I also get the impression you rather have 8 maximum; if so, stick to it - the larger the group the more the problems that tend to materialize.
Just a thought and good luck.