Yes, Ngaire Mark confirmed today that they are building the package for Silver Cloud Expedition voyage 1001 based on your request. Mark told me the voyage should be listed for booking next week on the the SS site.

New 15 day Antarctica voyage is now posted on the Silversea home page, but believe they have incorrectly priced the voyage keeping the same prices as the previous ten day voyage. Tho, would love to be wrong.

https://www.silversea.com/destinations/antarctica-cruise/ushuaia-to-ushuaia-1001.html