Thanks for this report, on of the highlights of January for me 
I changed the battery on my SBGX097 this year but it has never deviated by more than 1 second. What I found much more surprising it the Bulova Accutron II - a cheap watch with the low grade Precisionist movement (better ones exist). I practically never wear it and have had it since February 2016. Took it out last December and it was just 11 or 12 seconds off - over 22months! That’s some seriously good performance