I do the same thing with boxes of quarters at my bank and have no problems. It is a small branch bank with only two open teller windows (out of three) at a time. I have been cordial with the tellers and bring them doughnuts from time to time - mostly around holidays.
Since I swap out searched boxes for "new" boxes, it does not contribute to any coin shortages in any significant way.
I am extremely careful to always triple-check my coin counting so that I never miscount the coins I return. The clerks know this and never have to recount my return boxes - all they do is fetch me a box from the vault and return my box (with my initials on it) to the vault.
I am sure that it also helps that I have a substantial amount of money deposited in my bank in checking, money markets, savings and CD accounts.
The chip near the tree is commonly referred to as "snow on the roof." I prefer to call it "extra branch on the tree." They are difficult to find but are worth a small premium to collectors who appreciate various die chipped coins.
It sounds as if your sister does not believe what you have told her as to what you sold them for. "Tough luck," is what I would say to her, "either accept that or settle for the approximate face value of the lot." About twenty dollars ought to more than cover that!
Logic tells me that it is not possible for a legitimate coin to have both an "S" and a "D" mintmark, since all "S" coins are minted at the San Francisco mint and all "D" coins are minted at the Denver mint.
Would one you experts please explain to me how this can occur?