Sorry dude - 3A is a hardship deferment (family hardship, children). Paul could have gotten that too. Newt was eligible for the draft and he could have volunteered but he asked for a hardship deferment. Saying he was “not allowed to serve” is factually incorrect regardless of how you feel about Paul.
Plus, it’s a lot different moving from E-1 to E-4 as you likely did. That’s typical if you breathe and work hard. When I served it was 4 years to move from O-1 to O-3 regardless of how good you were. Then it was 3-4 years before promotion to O-4 (3 for me). Nobody moved from O-1 to O-4 in 4 years outside of battlefield promotions in combat back in WWII days.
But, thank you and your family for your service in any event. I do have great respect for anyone who serves honorably.