I just think it really depends year to year, Star Trek would make a different amount depending the movie that was before it, it definitely helped that nobody wanted to see XOW because of terrible WoM, similar to Neighbors with ASM2 (the target audience of neighbors is still part of the target demo for ASM2).
If Neighbors had followed something like The Avengers, I don't know if we would be seeing a 50m opening. I really think the 50m opening instead of the projected 35ish is a testament to the unappealing nature of TASM2.