Jeff, this may not be an esri supported approach, but worked for me as I could not find a good solution to update several features in my vector basemap without recreating the service. Make sure everything is the same with the level of detail and layers, etc.
You can rename the new tile package vtpk extension as zip and extract the contents.
You then browse to the location of the vector tiles in my case:
\\gisserver\c\arcgisserver\directories\arcgiscache\VectorCache\Hosted\VectorBaseMap\VectorTileServer\tile
and replace the L0* folders with the ones you unzipped and refresh the map view. Hopefully it works for you.
-Richard