You know, I'll be brutally honest.
I don't think Jesus looked outside to measure the position of the moon, then made sure his apostles understood the specific date, and if it was day or night.
Jesus Christ quite simply said "do this in remembrance of me."
How the Jehovah's Witnesses came up with all the stipulations, procedures, rules, regulations, policies, and protocols to follow, is completely beyond comprehension other than to say they have corrupted the simple instructions handed down by the Christ.