Exactly as I had states. It was a last ditch effort to save a Confederacy that Davis realized was dying. Why didn’t he make the offer in 1862? Because Davis believed that the Confederacy had a good chance of surviving at the time. By Nov 1864 all such thoughts were gone. It was a last ditch effort, just as enlisting 40,000 slaves for non combat duty, and a few month later allowing them to enlist in combat units. The dying gasp of diplomacy and social engineering to try and save the Confederacy.
We have a difference of opinion then in how we characterize it. You say "last ditch". I point out it was only a year after the EP and the war was very much still raging.
One year 11 months after the EP. The war was still on. But almost all hope of victory was fast fading from the Confederate view.
Lee’s army was penned in Petersburg, Sherman was about to start his march across Georgia. In one month, Hood’s Army of Tennessee would be crushed outside of Nashville. The city of Savannah would surrender to Sherman. Flour was 500 Confederate dollars a barrel, if you could find it. 95% of Southern ports were sealed off due to the U.S. Navy blockade. Two million slaves were now free because of the Union Army. The South was down to offering emancipation in exchange for Diplomatic recognition. Davis proposed enlisting 40,000 slave to support the Confederate Army. With a couple of months the Confederate Congress would consider enlisting slaves as soldiers. These acts are a pretty good indicator of how low the Confederacy had sunk.