As a former senior legal advisor at the SECAF Personnel Council, I was the action officer, lawyer and voting member on OGD Boards. 

Things you need to know about your OGD

What does the OGD Board look at?

How to prepare ahead of time if you know you will undergo an OGD.  

How does a reduction in your rank affect you post-retirement, including your retirement pay

AFI 36-3203, Service Retirements

https://static.e-publishing.af.mil/production/1/af_a1/publication/afi36-3203/afi36-3203.pdf

Blog article--The Tangibles and Intangibles of Retiring at a Lower Grade

https://ferahozbek.com/officer-grade-determinations-the-tangibles-and-intangibles-of-retiring-at-a-lower-grade/

Blog article--What you need to know BEFORE you decide to retire

https://ferahozbek.com/officer-grade-determinations-ogds-what-you-need-to-know-now-before-you-apply-for-retirement/