Not that I've noticed. Anything going through steam has to pass through the steam validation process internally. That goes for any number of games. I've noticed from games ranging from BF:BC2 to IL2:1946. There's always a lag because they're not just distributing it. They're running it through the steam exe with special parameters in most cases I can recall.
I think Ack-Acks point is that the update is delayed until it can be released at the same time for both versions.
Sorry, should have been more clear on what I meant by a single player game. Games like BF3, CoD are single player games with a multiplayer component, they aren't MMO games and Steam treats these updates differently. Games like BF3 and CoD are updated through the Steam client, meaning EA and Activision sends Valve the update and then Valve has to incorporate the update into Steam. This is why you can't use updates from the box version with the Steam version and vice versa and why it sometimes takes longer for game updates to arrive for Steam games. However, with MMO games like Rift, while the game is launched through Steam, the regular game client patcher does the updating, not Steam. This means AH wouldn't need to use Steam to update the game as it would update when the player logged into AH and update regularly.
ack-ack