I just asked my rep about this. They said that there are no discounts to the US, only Canada. As well the Ebay discount is just a lvl one discount. Also note that staring in Jan there will be a fee to process your manifests manually. I think it is $5. The email is below.
Hi Ryan!
Thanks for the link. Basically, this is introducing Power Sellers, such as yourself, to Canada Post. The discounts that it refers to are essentially what I'm offering. I have attached the level 1 rates so you can have a look. Again, unfortunately, this will only offer you a further discount on items mailed within Canada. Your US rates will remain the same.
As for the Electronic Shipping Tools, I really recommend that you give it a try. You don't have to continue to use them if its something that you don't ike. However, please keep in mind that in January we will be offering a 2%
discount to customers that use EST. EST also offers other benefits; being able to manage your account, ordering supplies on-line and being able to print your barcode labels. In January, there will be a manual processing
fee for customers that submit a manual manifest, so please keep this in mind.