How every team but 4 of them can average 305+ and yet have the league average be between 304 and 305?

Team Average weight Weight rank Rush avg. (YPG) Pass avg. (YPG) Total YPG
Ravens 327 1 9 16 16
Bills 323 2 12 15 15
Bengals 315 3 14 11 12
Dolphins 315 3 15 10 14
Chargers 315 3 5 8 5
Texans 315 3 12 3 6
Browns 311 7 11 13 13
Steelers 309 8 1 14 8
Titans 309 8 7 9 10
Colts 309 8 6 1 2
Chiefs 309 8 2 2 1
Raiders 308 12 16 6 12
Jaguars 305 13 8 5 4
Patriots 305 14 8 5 4
Jets 301 15 3 12 7
Broncos 295 16 4 4 3

NFC OFFENSIVE LINES
Team Average weight Weight rank Rush avg. (YPG) Pass avg. (YPG) Total YPG
Vikings 331 1 5 1 2
Cardinals 326 2 8 12 13
Cowboys 325 3 11 6 6
Eagles 322 4 10 4 5
Saints 320 5 14 5 7
Lions 318 6 16 13 16
Bears 317 7 6 16 15
Redskins 313 8 9 14 14
Packers 313 8 4 2 1
Giants 311 10 3 11 8
Rams 311 10 7 3 3
Bucs 305 12 13 10 12
Panthers 305 12 12 8 9
Seahawks 305 12 2 9 4
49ers 301 15 15 7 11
Falcons 295 16 1 15 10