Ah, it seemed like a mistake or an attempt to be disingenuous or something. I think it would have been more impactful of a point to list them in order of performance, and then a space, and then BvS and X3.
I didn't list them in 4th weekend order, because a bunch of comic films that didn't even manage $100M opening weekend were higher than those two. However. just for you:
The Big list of Fourth Weekends for Comic Book films w/ $50M+ openings (ordered by 4th wkd gross):
Avengers - $36.7M
Spider-Man - $28.5M
The Dark Knight - $26.1M
Age of Ultron - $21.7M
Iron Man 3 - $19.3M
The Dark Knight Rises - $19.0M
Guardians of the Galaxy - $17.2M
Deadpool - $16.7M
Iron Man 2 - $16.5M
Captain America: The Winter Soldier - $16.2M
Spider-Man 2 - $15.0M
Spider-Man 3 - $14.3M
Iron Man - $13.4M
Man of Steel - $11.4M
Thor The Dark World - $11.0M
X2: X-Men United - $10.5M
X-Men Days of Future Past - $9.8M
Thor - $9.5M
Batman Forever - $9.2M
Batman v Superman - $9.0M
X-Men Origins: Wolverine - $8.1M
Ant-Man - $7.9M
The Amazing Spider-man 2 - $7.8M
X-Men The Last Stand - $7.8M
Superman Returns - $7.3M
Captain America: The First Avenger - $7.2M
Fantastic Four - $6.9M
X-Men - $6.8M
Amazing Spider-Man - $6.7M
X-Men: First Clast - $6.7M
The Incredible Hulk - $4.9M
The Wolverine - $4.5M
Fantastic Four : Rise of the Silver Surfer - $4.2M
Hulk - $3.7M
Green Lantern - $3.1M
Watchmen - $2.7M
EDIT: And as a bonus
Fourth Weekends for Batman films
The Dark Knight - $26.1M
The Dark Knight Rises - $19.0M
Batman - $15.1M
Batman Begins - $10.0M
Batman Forever - $9.2M
Batman v Superman - $9.1M
Batman Returns - $7.7M
Batman and Robin - $4.1M