So here's the verdict. Using real data from internet won't work. WOFF uses some other info to dictate sun positioning.
Here's Major Test Ickle on 4 January 1917 at 8:00 am. According to timeanddate.com the sunrise on that day occurred at 8:50 am.
Here's Major Test Ickle taking off on 2 April 1917 at 6:01 am. Sun should be rising at 6:22 am.
Looks like another method needs to be devised to match WOFF sun status.