i just tried to export track archive from one session and separately tempo track to import both to a new same session…
it doesn’t match ! this is really painfull !! nobody else is using that function ?
further tests :
export / import track archive = all types of tracks except tempo related to timecode
export / import tempo track = tempo only NOT RELATED TO TIMECODE ! 
just start from begining of session.
exporte / import tracks for other session = no tempo track
