Hi, I cannot comment on the data integrity, but there is no need to export the file to hold different durations against a project. Please see this blog https://www.applepark.co.uk/optimistic-and-pessimistic-views-on-a-single-gantt/ for how to do this. Note that the PERT functionality I used in this blog was removed from Project 2010, it can be re-implemented from here… https://blogs.technet.com/b/projectified/archive/2009/11/24/3296207.aspx, though in truth you can use any of the custom duration and start/finish fields.
