Free Postage For Additional Items

[carnabycool]

I am considering buying more than one "buy it now" item from an eBay listing (on eBay US) that offers the same item with different colour and size options. There is a field to change the quantity from 1 to 2 . The postage information at the bottom of the listing shows the postage cost and states that additional items are free postage.

I would like to buy the item in 2 different colours. It is a listing that has been set with an "immediate payment" requirement. . As I would need to make 2 separate purchases , one for each colour, it seems to me I would be charged postage for each purchase (i.e no free postage for the additional item from the same listing) without a combined invoice from the seller. However the seller insists the "cart" will show automatically show the correct total for both of the items. Is this the way these kind of listings work?