Texan,
Some quick comments about your sample and what I like to see in Commander's letters.
I like to see at least 3 things in a letter (so long as they support the member's position).
First, I like to see a statement of introduction and basis for the observations. Example. "I am Airman Smith's Commander and she has served under me since her assignment to this Flight 18 months ago. In that time, I have observed her duty performance while deployed to Afghanistan for 9 months, and in garrison the remainder of the time. Normally, I observe her directly 2-3 times per week."
Second, a good letter will focus on each medical condition and the impact of them on specific duty tasks. This is very important information that the PEB needs to make a correct decision. Absence of this is also one of the most common deficiencies in letters that I see, especially when the member has more than one condition. In many cases, it is helpful if the Commander addresses symptoms rather than conditions.
Take this example: "SGT Smith's back condition prevents him from adequate performance of his daily duties as a Senior Wheeled Vehicle Mechanic." Seems pretty good, right? But, if SGT Smith has both Thoracolumbar and C-Spine issues, this may actually hurt when compared to something like this: "SGT Smith's neck condition severely limits his range of motion to the point where he cannot effectively work on or under military vehicles. His persistent lower back pain and spasms make it impossible for him to lift tool boxes and to remain in a fixed position while working on engines as is required on a daily basis as a Senior Wheeled Vehicle Mechanic." The first statement only addressed the "generic" back condition and made a conclusory statement of the Commander's opinion. In most cases, this might lead to a rating for thoracolumbar issues (especially if the medical documentation is clear). But it does nothing to address the C-spine condition. The second statement gave specifics as to what the symptoms were and how they impact duty performance. On the basis of this statement, both low back and neck conditions may be rated. I think that letters like the first statement is often a result of a member having one main condition that bothers them the most. If I have both bad shoulder pain that is constant and a knee that sometimes locks on me, I may tend to focus on my shoulder more than the knee (perhaps because of keeping the explanation simple, because pain oftentimes is more bothersome than occasional orthopedic problems, etc.). My supervisor may excuse me from organized Physical Training due to the Shoulder that I have often complained about and s/he may not be aware that I have a knee problem. If I did not have a shoulder problem, I would probably need to be excused from Physical Training as well. But, the point is, the Commander, when writing the letter, may remember me as the Soldier with the "bad shoulder" and not even think of the knee.
Very helpful is if the Commander can state things that you have failed at performing. Example, "SGT Smith's limited Range of Motion has made him unable to check under vehicles and rendered him useless as a member of the Mobile Maintenance Team. I relieved him of these duties last quarter after the number of annual vehicle services he performed fell to a point to make him more of a hindrance than a help." Contrast that with sort of general statements like, "I cannot see how he can possibly perform his duties due to his limitations." This does not help the PEB in coming to a decision and is the sort of opinion statement that may not receive much credit. Also, note that it is not helpful to comment on administrative limitations. In the previous example, instead stating, "SGT Smith's physical profile keeps him from duty on the Mobile Maintenance Team," only tells the PEB that someone thinks he can't do something. It is not clear that were he allowed to, he could not. And the PEBs view themselves (quite correctly, legally, prior to approval of the case) as the ultimate arbiters of these matters.
Finally, I like to see the administrative matters addressed, and reconciled if there are inconsistencies with the previous sections of the letter. For example, if the narrative is clear that the member is unable to perform, but the member's last evaluation states how well he performed during an exercise, the Commander might address this by saying, "Though LCpl Davis' evaluation reports indicate superior performance over the last rating period, his physical condition has deteriorated rapidly over the past six months. The awards he earned and his performance at the Battalion Field Training Exercise were within the first two months of the rating period. Unfortunately, he is not able to perform like he did before his conditions worsened."
Things I don't particularly care to see are recommendations as to unfit/ retirement outcomes unless the Commander is an General/Flag Officer. Fitness determinations are the province of the PEB and they often view recommendations that someone be retired in close cases with skepticism. If the nature and severity of the conditions are so clear, then the recommendation is unnecessary. Plus the letter should support the conclusion in the first place. Note that I did not include recommendations as to fit findings. I tend to think these are okay, relatively speaking. This is my opinion, some may disagree. I also think it is counter-productive in many cases to talk about the long and great career the member has had, that they have dreamed of wearing the uniform since grade school, and are otherwise "great performers" (the last, especially). This is not to mock anyone, I think that the PEB already has your service records and reviews them prior to making a decision. If you have a notable career, they already know it. If you do not, the letter will be discounted. Mention of your desires (except for retention in close cases) generally carries no weight. And great performers may be more likely to be found fit on some conditions. All in all, I see little to be gained with these types of statements and some risk.
Remember, the idea is to provide the PEB with information they can use to make a better decision in your case. If the letter is weak on details, based solely on opinion, or inconsistent with the other admin data provided to the PEB, it may be not given much weight. It is not always possible to get a helpful letter. Having a good one can be a great help. Having one that hurts your case needs to be addressed by providing evidence that counters the letter (objective medical evidence, statements from other leaders, and personal testimony, for example).
Questions?