Woooo, I just got my second $30 rebate. First one came end of December.
Now the story. I contacted the promotion company to ask about the second rebate. They said the rules/regs stated one per household/email. I explained that I contacted BP/Castrol prior to buying the second one and the rep said one rebate per unique invoice and I could get multiple and I had the printed/screen shot from website. I sent them the pictures, copies of both receipts 1 week apart and it was being sent to review department. They were pleasant to deal with and said they would get back to me. That was less than a week ago.