Hi PhilthyCollins,
I cannot give you a definitive answer as to why the shipping quote you received from Auctiva for the item in question was greater than the one you received from eBay, but I have heard that eBay offers postage discounts to certain sellers so perhaps the rate you were quoted by eBay reflects some sort of discount.
The rates associated with shipping labels purchased through our site are set by our provider and, although they should generally be competitive with other online USPS shipping providers, I would not think to discourage you from using the service that provides you with the best rate.
If you need any further assistance with your account, please feel free to contact our Customer Support team by mousing over the "Help" tab within your account and selecting the "File Support Case" option.
-Mike
