when I say start and end at the same time this of course refers to the time scale used, for example if I am talking years and say Mr. Adams started his project

when I say start and end at the same time this of course refers to the time scale used, for example if I am talking years and say Mr. Adams started his project in 1920 and finished in 1928 and then later I say Mr. Bronder worked on his project in parallel to Mr. Adams I would expect that meant Mr. Bronder started his project in 1920 and finished in 1928 - not that they started the exact same minute - because the time scale used is in years.