EXISTING—A tiling scheme from an existing map service will be used. You must specify a map service in the service_file parameter. Choose this option if your organization has created a tiling scheme for an existing service on the server and you want to match it. Matching tiling schemes ensures that the tiles will overlay correctly in your Maps SDKs application. If you choose this option, use the same coordinate system for the source map as the map with the tiling scheme you're importing.
Will the tile package writer be enhanced in a future version to accommodate alternative tiling schemes with different pyramid levels and coordinate systems?