A spokesperson for the Met Police said that their lower costs were due to a decision to reduce police presence inside stadia.
"We don't police inside the stadium and haven't for a number of years,'' the spokesperson said.
"We're there to prevent crime and disorder. The Met's Football Unit does look at the intelligence packages on each game but as a rule we don't police inside.
"What we are able to charge for is what [the clubs] actually own. So where [officers are stationed] on the public highway, we can't charge. For example, at Arsenal there's a road called Drayton Park Avenue in the lead-up to the [Emirates] Stadium, and that's a public highway, so policing that area could not be charged for.