I think that it is something that sellers sign up for and mine obviously did although from what I can gather he did not realise it was compulsory as he tried to give me a slightly lower rate but the system wouldn't let him. TBH it is probably swings and roundabouts, the shipping costs themselves aren't too bad ~$10 but the major costs come on the customs tax. UK customs as well as 20% import duty charge a flat rate £8 (about $12) handling fee per package so if you have several items you can save quite a bit of money by sending them together in one parcel. The new (eBay) system charges an inclusive up-front fee covering both handling and duties (in my case about $15) chargeable on each item when you pay eBay, so no savings on handling fees now . Additionally I have had items where customs haven't charged duty on the package, always a bonus . So in summary if I get hit for all charges it is probably the same under either system, but now I don't get any possible savings and those are presumably pocketed by eBay or their shipping partners.

http://pages.ebay.com/help/buy/shipping-globally.html