Paul, I went to the "Help" tab at the top of the ebay.com website. I searched on combined shipping, and the following link came up:
https://www.ebay.com/help/buying/shipping-delivery/shipping-rates/saving-combined-shipping?id=4063&st=3&pos=3&query=Saving%20through%20combined%20shipping&intent=combined%20payment%20%20and%20combined%20shipping&lucenceai=lucenceai&docId=HELP1020

Note the yellow box that begins "Starting October 24, some buyers ..."

That's what I was referring to. Maybe this new option is being tried out on "some buyers" (not all) and it's in test mode? Not a permanent option at this time, but maybe in the future.

In the meantime, if I win multiple items, I plan to pay via the Shopping Cart, and it that doesn't combine shipping, I'll email the seller and ask him/her to invoice me with combined shipping.

An eBay work in progress it seems.