How does an E6 have 6 service stripes?

Not a day over E-5...
Enlisted USN 9Aug1984. Age 22
IRR 1994 age 34
NAVRES 2000 age 39
Enlisted Army, 3d ID 2007, age 46
Army Reserve age 49.
"Permanent and Total" VA 100%
Chapter 61 discharge 29Oct2014

Wow, really? And you’re a human resource specialist? I feel for anyone who’s records you review for accuracy.

How are you confused? He has been in 18 years and earned the rank of SSG. My suggestion to you is be quiet and learn about rank.

PFC O'Hara,
If he is and E6 with 6 stripes, it does mean 18 years service which basically means a promotion every three years. This is possible if you are not in a combat related MOS or get passed over for promotional boards. If he did have an article 15 it doesn't necessarily mean be lost rank. I don't know if it has changed or not since I served, but there were three types of Article 15's.
Summarized
Company grade
Field grade.
Combat MOS generally makes rank quicker. Usually 20 years of service for enlisted is at least E-7 but again it depends on the various circumstances.
Hope this helps,

Look here BOOT, most enlisted retire out as an E6 definitely the more common trend. How about you let your balls drop a little bit and focus on trying to become at least an NCO before you start questioning the years of service of a SNCO.

I made E-4 3 times in 24 years of service, but I'm much better now

I have seen E-4s with 6 or 7 service stripes. If you are a higher rank and have 21 plus years of service and get busted down to an E-4 then you will retire as an E-4. I saw an E-5 get busted down to an E-4 and retired 3 months later with 20 years service. When I retired there was a Sergeant E-5 retiring the same day with 20 years service. I have also seen and E-6 or E-7 with 10 service stripes.

I'm an E4 and I will have my 4th stripe in January. Having a shitty command and and multiple injuries requiring surgery that have resulted in long term profiles has kept me from advancing. The most severe of which is a career ender. I am now waiting for the med board to finish so I can get out and get my C5-C6 vertebrae fused. Go army.

My wife, by Brother in law, my younger brother, my cousin, and 4 of my close friends all left with more than 20 years of service as E-6. None of us had issues in service, but all had MOS's that were typically slow in promotions. I had breaks in service due to Medical Discharges and waivers to return and then there is the world wide deployability (due to medical profile). Little things like that tend to put a damper on promotability. So knowing that was the possibility in my future, I opted to double my MOS's to become more employable in the civilian sector over rank issues at retirement. The Retirement pay is negligible from 20+ E6 and 20+ E-7 due to TAXES. And, there is no real advantage gained between an E6 and E7 when going into Federal Civil Service. It then becomes a matter of personal decisions and Rank Status as a Senior NCO status upon Retirement. If you can personally live with your choice/circumstances at retirement then you have achieved your goal "Retirement."

Have they never heard of prior service? One easy way to get there as an other service Vet.