Thanks Mel for the correction.
But here's what I based my reply on.....
On my first patrol in GWX I bagged The HMS Rodney, 3 Flower Corvettes and a Large Merchant. Total Renoun for that patrol was 1558.90 giving me a total of 2358.90. I started out with only 800 after getting the officers and crew I wanted from the 1500 original Renoun. I then docked with the Bessel at Vigo Spain for resupply and found when I restarted I was promoted from Lt. Jr to Lt. Sr. A far cry from accululating 5000 in Renoun. So if there's a bug, it seems renoun has no bearing on promotions. I've even seen the same in Vanilla SHIII as I received the Knights Cross with Diamonds and Swords on my 7th patrol. That's the reason I said what I did above.