In which timezone do you live? I want to understand at which time it has switched in the place I live. I also want to uderstand how precise this spreadsheet's dates are.
I live in UTC+1 time zone. Forum appears to me to be UTC so there is just one hour of delay. OP says time of the spreadsheet is GMT (which is the same as UTC).
Anyway, I wasnt upgraded at the exact time predicted because I was refreshing every 5-10 minutes and it happened between 9:10-9:25 (GMT or UTC), not 6:46.
By the way, thanks to the OP for the work. Pointing out there is a small delay is to improve the spreadsheet.