Selling multiple items with calculated shipping
I have previously only used calculated shipping (entering the package weight and dimensions) for select items. All of my other items use flat shipping.
How does calculated shipping work if you sell multiple items?
For example, say I have an item that fits in a 4x4x4 box and weighs 6 ounces. If someone buys more than one, and they don't fit in a that same box and obviously weight more, what happens with the shipping, both in terms of what the seller pays and my cost?
Or what if someone buys multiple different items, each with their own unique package size and weight?
I'm thinking about using more calculated shipping to hopefully be more competitive cost wise, but I also don't want to get screwed over and lose money on the shipping because eBay's system calculates the shipping on a package size and weight that no longer applies.