According to the publications, I think something is a bit off....
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it-2 p. 268 Lord?s Evening Meal ***How
Often Observed. According to Luke and Paul, when instituting the Memorial of his death Jesus said: "Keep doing this in remembrance of me." (Lu 22:19; 1Co 11:24) From this it is reasonable to understand that Jesus meant that his followers should celebrate the Lord?s Evening Meal annually, not more often. The Passover, observed in remembrance of Jehovah?s deliverance of Israel from Egyptian bondage in 1513 B.C.E., was commemorated only once a year, on the anniversary date of Nisan 14. The Memorial, also an anniversary, would appropriately be held only on Nisan 14.***
km 3/87 p. 1 Preparation for a Special Occasion ***This occasion is properly celebrated every year on Nisan 14. In 1987 the Memorial of Christ?s death falls on Sunday, April 12. Are you making plans to be there?
*** This date mentioned above even lines up with the date converter
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rs p. 269 par. 2 Memorial (Lord?s Evening Meal) ***Jehovah?s Witnesses observe the Memorial after sundown on Nisan 14, according to the reckoning of the Jewish calendar that was common in the first century. The Jewish day begins at sundown and extends until the following sundown. So Jesus died on the same Jewish calendar day that he instituted the Memorial. The beginning of the month of Nisan was the sunset after the new moon nearest the spring equinox became visible in Jerusalem. The Memorial date is 14 days thereafter. (Thus the date for the Memorial may not coincide with that of the Passover kept by modern-day Jews. Why not? The start of their calendar months is set to coincide with the astronomical new moon, not the visible new moon over Jerusalem, which may come 18 to 30 hours later. Also, most Jews today keep the Passover on Nisan 15, not on the 14th as did Jesus in harmony with what was stated in the Mosaic Law.)
Even if the JW's do not follow the Jewish dates as mentioned above, it would only be off by 18-30 hours.
Catch, scratching head