Free shipping on order less than free ship price

I've double checked my Free Shipping Options - set for free shipping on orders over $95 - it's always worked fine and no changes have been made there.

Today a customer made an order for one $70 item, and somehow got free shipping. I made a test order of the same item, and my only shipping option was correct - DHL Ground, for the correct fee.

Anyone ever had this happen, or have any idea what I could be overlooking that would allow free shipping on an order under the correct price?

(I wrote the customer asking at what point in the order process he got the free shipping option, but of course don't know if he'll write back on that. If I get any info I will provide it in this thread.)

Thanks...!