Addressing an officer by rank and name

The SFC is using his "interpertation" of the regulations. What you did is correct by the book and by practice.
The only other thing that I have to add is that the word is not "Sirs" it is "Gentlemen" if there is more than one present.

Sounds fine to me, especially if there were other officers in the room. If you just said sir, then which one? The only thing I remember when I was in Army ROTC that it seemed improper to call an officer by his/her rank alone without last name unless they were a GO.

Long story short, I don't think you did anything inappropriate.

You can address them by rank and last name or by Sir/Ma'am. That is the proper method. If peer or supervisor you call by rank and last name if in front of subordinates and then by just last name or first name if you are alone or in a group at his/her level and above (ie: address LT by their first name when you are a BC and the S3 and XO are present). Though many NCOs are upset that officers call each other by their first name. It is not within the regulations, but is a common practice.

Think you got your answer. Nothing to add that LTC (Join to see) and TSgt (Join to see) didn't cover.

This reminds me of people getting their panties in a bunch over addressing NCO's in the Army... IM A MASTER SERGEANT! Uh huh... E5,E6,E7,E8(without a diamond) are addressed as Sergeant. E8 with diamond, First Sergeant, and E9 whether SGM, CSM or SMA are addressed as Sergeant Major. As long as you know your regulations, good to go...

If I had to get a superior officer's attention in a room full of superior officers, I said, "General Smith, sir." The next word out of my mouth was sir, followed by my question or statement.

I believe you were doing the right thing, but there is a certain amount of horseshit involved, and it varies by service. In the Navy and Marine Corps, it is more correct to address an officer by his rank and name or just rank, rather than "Sir", but "Sir" is fine. In the Navy (and, perhaps, Coast Guard), addressing a junior officer (LCDR and below) by "MIster"(Miss/Mrs.) and his (her) last name is technically reserved for officers senior to him(her), but is often used as a sign of familiarity or affection by juniors, particularly substituting the first initial of the last name. (To my Divisions, I was always "Mr. G".)

The Army goes the other way, where "Sir" is preferable to rank and last name or rank alone, except, of course, when it would cause. confusion. Don't feel bad: my forward-deployed boss at CENTCOM was an Army O-6, I a Navy O-5. I thought I was being more respectful by addressing him by his rank and last name. He asked me if I thought he was an asshole, because I wasn't calling him "Sir" when I'd greet him in the morning. We were simply having a translation issue (which went both ways, because sometimes at meetings, he would simply refer to me by my last name...which I found offensive, even though, as the Senior, he may have the prerogative to do.) He would also refer to Chief Petty Officers as "Petty Officer", rather than "Chief", which is, of course, offensive. I'd set him right on such matters, courteously and in private, of course.

Rank and last name is always appropriate regardless of the rank.

If you are around Officers long enough, you will notice that seniors will call their peers and subordinates by first name.

That SFC was an idiot. I address every single O-grade in my unit by rank and last name. Why? Because I'm a CW3, and the second lowest ranking officer in my unit. If I holler "Hey Sir!" every single male officer is going to turn around. If I holler "Hey Ma'am", every single female officer is going to turn around. That causes confusion, for what?

Any O-grade who would chastise me for addressing them as "Rank Lastname" is an O-grade who's about power rather than authority. I tend to walk away from those kind and not talk to them. I'm at the point where I can get away with that too...so it's all good.

I think you were 100% correct in the way you handled it...if you had yelled "Sir (or Ma'am)" across the room, how many people would have looked up confused?

I am not someone who memorizes every regulation, but in my experience (and understanding of common sense) you did the right thing.