Since you gave two predictions, one answer isn't really enough. I think you may be close on the 3-day figure, but I think you're a little higher than it will end up for the 4-day figure. Typically Memorial Day Monday box office for a movie on average is about 70-75% of the average for the Friday to Sunday before it, with very few movies going more than 10% away from that range in either direction. For Poltergeist you've got it at about 90%, which while within the realm of possibility, is very rare. I'm guessing the three day total will be $22 million and the four day will be $27 million.
Since you gave two predictions, one answer isn't really enough. I think you may be close on the 3-day figure, but I think you're a little higher than it will end up for the 4-day figure. Typically Memorial Day Monday box office for a movie on average is about 70-75% of the average for the Friday to Sunday before it, with very few movies going more than 10% away from that range in either direction. For Poltergeist you've got it at about 90%, which while within the realm of possibility, is very rare. I'm guessing the three day total will be $22 million and the four day will be $27 million.