Is this suspicious?

[Bingo]

I listed an item at bidding price of $35, but a buyer bid $48 and paid right away.
I remember that I set Buy it now price at $39 (because normally I just set 10% more than bidding price), but since the buyer bid $48, so I don't know if I set BIN at $48 by accident, or there is something suspicious here.
It's a PO box address.
What is your opinion on this?

[jeffweico]

I think that you set the price at $48 by mistake. When using Buy It Now, I do not think there is an option to enter a higher amount than what the seller is asking.

[Bingo]

You're right. I just figure out that I set BIN at $48. This time I'm lucky because I have listed this item for a long time, but when I set a higher price, it becomes more attractive haha.