Anyway, the seller should be able to do a trick, like increase the estimation shipping cost or the actual price to replace the deposit.
Looks like that. I'm going to charge my own fee for my service, and I'll absorb unexpected shipping costs and Bitcoin price fluctuations.
Shipping cost is not the only problem for you, sometimes the products won't get approved by customs if its send by someone personal on particular country so you need to analyse the receiving country's laws as well before making an estimation because he might say that he didn't receive anything so asking for payback from escrow.
Customs shouldn't be a problem. Product is legal. It's not heavy; it fits in a regular mail package. I think any possibility of surprised custom costs should be paid by the buyer and it should be agreed upon with the escrow.
I'm still at the stage of looking for an escrow now. Just saying.