When Phil Coulson first introduces himself to Pepper Potts, he says the following:
Agent Phil Coulson: I'm Agent Phil Coulson with the Strategic Homeland Intervention, Enforcement and Logistics Division.
Virginia 'Pepper' Potts: That's quite a mouthful.
Agent Phil Coulson: I know. We're working on it.
At the end of the film, the agency is suddenly S.H.I.E.L.D.
Virginia 'Pepper' Potts: Agent Coulson, I just wanted to say thank you very much for all of your help.
Agent Phil Coulson: That's what we do. You'll be hearing from us.
Virginia 'Pepper' Potts: From the Strategic Homeland...
Agent Phil Coulson: [interrupting] Just call us SHIELD.
The way the scenes play, it implies that S.H.I.E.L.D is a relatively new group, but we know from the subsequent films that this is not at all the case.
Is there a particular reason why Coulson first introduced himself like that?