Thanks for the very speedy reply!!
I’m sorry to have troubled you. I think I have figured out the answer. I was importing messages labelled with Eastern Time Zone timestamp, but my computer is now on GMT +8. Eaglefiler was relabelling the message timestamps for my current time zone which is 12 hours later than EST. The one hour daylight savings meant the shift was sometimes 12 hours and sometimes 13 hours - a bit confusing. My fix is to just set the timezone back to EST when importing messages received when I was in that part of the world.
(I was also thrown off by an extra variable time difference (on top of the 12 or 13 hours) of a few minutes up to about 15 minutes, which seems to have to do with Entourage stamping messages for time received at my local server, and Eaglefiler stamping messages with when they were sent. That is less of a problem for me, so I’m ignoring that).
Thanks very much for Eaglefiler, I’m finding it a very helpful program!