The lobby firms actually bill based on the number of interactions they have with public office holders. So they manage to keep those records nice and up to date when it comes to sending the invoice to the client.
I don't understand why it would be so difficult and onerous for them to keep those exact same records. In fact, they could merely be photocopied for the purpose. I'm talking about the comment made earlier here, which was that it's so onerous now to record that 15-minute phone conversation. Well, you bill for that 15-minute phone conversation, so your firm is obviously recording that somewhere already for commercial purposes.