>>4148066 (lb)
Considering the -23 was very well established at the time as indicating the beginning of a countdown, I think there is a VERY high chance this is true.
We should maybe look looking at Dec 5 as what would have been a jumping off point, starting -23 days until Dec 28.
Also worth considering that this example showed us the concept of -23 being applied at various levels (minutes, hours, days).
Maybe -23 has relevance in the overall timeline, perhaps indicating that the plan will reach significant milestone at 23 months from the start point (September 2019)