Not necessarily.
If you create a project template (with your tempo map) leaving your PITA midi tracks where they are.
save it as a project template. Next time you open this project template, your midi tracks will be there as will the tempo map you created.
You wont have to copy the newly created MIDI tracks. They will already be there.
this has come in discussion before, and to be honest, im not a big fan of project templates retaining data.
If I create a project template, I expect it to be a template, not a project filled with data. but it is.
And it is helpful for situations just like yours. if you save a project with data in it, the template will retain all that data in the project.
I could be misunderstanding you, if so, my apology's. im just trying to help you find an easier way

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As far as your idea though about Tempo maps. its a good idea and I would vote for it. unfortunately this thread is in the wrong place. Put it in the feature request section of the forum where users can vote on it. you got my vote.