Ooooh it’s a Roman versus modern counting convention argument, the best.
If I gave you something on the 20th and said you had one day to get it back to me, what day would you get it back to me by?
But also, you would literally have 8 days to work on it.
Modern counting typically starts at 1 whereas Roman counting started at 0, and we’re still inconsistent about it.
It's not about starting the count at zero or one. It's about considering what a day is.
Pretend it is family porn night at the H&H household. Right after the money shot, you tell the kids that it is time for bed. You look at the clock, and it is 12:01 a.m. Since they just watched an exciting movie and since they have west virginia roots in their family, your children want to sleep in the same room. You tell them "make sure you kids get some rest, because tomorrow we are going to DisneyLand."
Does that mean tomorrow is the day they wake up or the day following the day they wake up since it already is "tomorrow" (12:01 a.m.).
Another example:
Assume it is Friday night at 11:50 p.m. Your wife gives you permission to go to the AVN Awards show that starts at noon on Sunday, but only if you get all your chores done. You contest that it only gives you one day to get all of them done, which isn't realistic. She counters that she is giving you three days (Friday, Saturday, Sunday) to get them done before the awards show.
Is it fair to count Friday (10 minutes left) and Sunday (maybe an hour or two before you would need to go to the awards) as two days? Of course not. The same applies to Meg Black's counting.