I was having some difficulty getting an abstraction for Max 5's ITM metro features to work correctly, due to some constraints on the order of the @autostart and @transport attributes. This patch should explain everything.
In the subpatcher, because of the default attribute values and some issues with the order of things coming out of [patcherargs], things didn't "just work". I have a solution using [deferlow] to make the @autostart attribute get delayed slightly while the subpatcher initializes the other attributes. I found I have to do this with @autostartime too.
Is this a bug in [metro]? If not, I'd request that switching the @transport of a metro will maintain the current attribute values like @autostart and @autostarttime.