Here is a “live” case study that may be helpful to you on the business side of dealing with insurance.
I ended up having a SRP claim denied twice.  So I had to talk to a dentist reviewer on the third try.  The reviewer was pleasant to talk to, but was obviously trained on how to fight with every possible come back.  He just picked the wrong person to try to disagree with. 
So here is a basic outline of how to fight these on the phone and what to be prepared for:

1) X-rays – there was minimal, but obvious vertical attachment loss in places, so I got him first to agree to seeing that.  If they want to fight this, you fall back on the true definition of perio, which is from your clinical attachment loss (CAL).

2) Reviewer – “There are only 4mm pockets on the top….and “only” a couple of 5-6mm pockets on the lower.”
I started talking about clinical attachment loss shown, and since we do have good measurements of gingival margins (GMs) it was easy to get him to see the CAL.  I also got him to agree that the AAP and periodontists define perio by CAL, not pockets or x-rays.  Every quad when counting CAL has multiple teeth with problems that justify SRP.

3) Photos – we did not talk about this since we had clear photos, but it always helps to have pictures of the perio probe in place showing not only the depth, but also the blood.

Now, the one failure in this case that caused the conversation to last even a couple minutes was not marking GMs on every tooth.  He did bring up swelling in tissues and possible pseudo-pockets.  We had enough measurements of GMs to get undebatable CAL, which closed the case and had him agree to approve treatment.  You should make sure to mark literally everything, including zeros. This will remove the ability for them to argue pseudo-pocketing.

Moral of the story: your perio chart is everything.  Fail to get every point, especially bleeding and Gingival Margins to have accurate CAL, and you will deal more with denials.  Have a FULL perio chart and there is not much to debate. The most common concern I see when someone sends me a perio chart they want my help with is the lack of full data, most specifically the GMs.  Remember, without a baseline GM, clinically it is impossible to determine CAL, which is what is required by the AAP to come up with a diagnosis.

When talking to reviewers, remember they are dentists.  You can have whatever opinion you want about them with what they do, but you will get farther being professional over being rude.  The entire conversation with this reviewer was pleasant and he nicely at the end agreed to approve the case.  These dentists potentially can help you, getting upset with them (or them upset with you) is not the way to go.

Remember insurance companies are after the low hanging fruit, specifically offices that are easy to deny due to missing information or lack of pushing back. Push back and they will go after another piece of lower hanging fruit. We have submitted over 300 cases of SRP this year, and this is only the second case of perio that went past submission #2.

If you are interested in more ways to get paid by insurance on legitimate claims, I have an online CE course that goes into a lot more detail: “Understanding Insurance and PPOs.”