Brother, they end the day the same, on a "morning". I don't have to do any heavy lifting here because God has done it for me. You fell into God's plan to acknowledge that you see it in one passage before God's word convinces you with another passage.
The meat of their fellowship offering of thanksgiving must be eaten on the day it is offered; they must leave none of it till morning. (Leviticus 7:15 NIV)
The end of a day above is the same as the end of a day below.
Do not leave any of it till morning; if some is left till morning, you must burn it. (Exodus 12:10 NIV)
The next passage is from a Rabbi trying to make since of it.
A Long Day
Also note that, in a certain sense, the celebration of the 15th is considered to be an extension of the 14th. How so? With regard to sacrifices, the verse states, “And the flesh of his thanksgiving peace offering shall be eaten on the day it is offered up; he shall not leave any of it over until morning.” In other words, if you were given one day to eat an offering, the day consisted of the daytime followed by its night (unlike all other purposes, for which Jewish calendar days consist of the night followed by the day). Thus, as far as sacrifices are concerned, the night after a sacrifice is brought is an extension of the day it is brought.
Therefore, when it comes to the celebration of the Passover sacrifice, while it was eaten on the 15th, it was considered to be the same day as the 14th. (Rabbi Yehuda Shurpin)
United in our hope for the soon return of Jesus, Jorge