You are joking right? Where do you get your numbers from?You are 100% guaranteed to develop cracks with the old motors. Return it immediately, tell them you received a used item and you paid for new. They may offer a discount refund. It's up to you to decide. Weather you receive a new motor is a different question. You are guaranteed new motor (and 100% guaranteed no cracks) if you purchase directly from DJI.

Please do not spread dis-information on the forum.