Does anyone know the process surrounding promotions for soldiers in IMA status?

First, let me provide some background. While I’m a company grade officer in the Army Reserve, I’m a retired GS-15 who is kick starting my military career after being in the IRR for 21 years as a “Key Government” employee. In 2017, I began drilling for pay and points as an IMA s9ldier assigned to an AC unit and have enjoyed being back in uniform again. As I’m getting back into being a soldier again and my military education in line with promotions (date of eligibility for O-3 was June 2000) I was trying to decipher the process. As I understand the regulations for promotion, once I’m promoted to O-3, my date of rank will coincide with my DOE, June 2000. After further reading of the regulation, my interpretation is my eligibility for O-4 will be the maximum years at O-3 which will place my my new DOE at June 2007 for promotion to O-4. Is this a correct interpretation of the regulation or am I wrong? Anyone with comments or insight regarding the regulation would be more than welcome.

The reason, I’m asking is I need to prepare my civilian employer for the military education requirements that come with my desires to have a fruitful Resrve career. While they are extremely supportive, like anyone else they don’t like surprises and I want to prepare them for any future abscences.