Staples Paper BOGO half off + $82 REBATE for $74+tax MM YMMV

Not sure if this is an error, but I went into staples today to buy two cases of paper ( here ). First one rang up $55.99 and second rang up $27.99.
I used this coupon , to take off $5 for each case.
My receipt is attached. I will try this again this week, I live in Southern California. YMMV Hope this works for someone!