Went to my selling dealer to purchase some WS for a drain and fill on my Sienna. Turns out they only have it in a drum for their own use and wouldn't sell me a gallon if I brought a container. Looks like Amsoil ATL for me.
Brett, you need to find another dealer. Even way out here on Cape Cod, the local Toyota dealer happily sells me quarts of WS for my sister's RAV4 and B-I-L's Corolla.