[quote=@Jotunn Draugr]
<Snipped quote by Raven_Operative>

Ah shoot, should I have responded in a more casual way?
[/quote]

Naw it's fine. That's military ranks 101, though.

Observe: http://www.army.mod.uk/structure/32321.aspx

The Officers are the only ones you address as 'Sir'.
The Enlisted (see: Other Ranks section) are addressed by rank.