@KARFA as always spot on, but not being an expert, and not personally having been in a position of leaving it so tight for a status upgrade/retention, and knowing BA Systems are not always the most reliable, my advice would be:

take a screenshot of your TP’s etc on the app the day before the reset, also of BP’s for the flights before the reset date but due to post afterwards. I’m sure this might make things easier on the likely phone calls / e-comms you might need to involve yourself in if it goes awry. This should hopefully account for even the most difficult potential beaurocrat / system says no you may face, (though my experience has shown vast majority not to be like that)

hope for the best / plan for the worst....?