"Generally" by Sept/Oct, we have lots of undergrowth, which adds a lot of food value.
I'm not going to argue one way or other, I really don't have a clue - but, my hired hay crew only had one experience doing what I will have and they all rotted - so, I'll let him make the call. It's not just mixing wet w/ dry, the dry is old and rotting (sat under snow all year).
And yes, all the "experts" say it HAS to be a certain moisture, but, we do not go by the book. We have had hay that was "hours" away from being ready to roll up dry, and the weather turned. Rolled all up & wrapped. Perfect.
They generally mow in the morning, have lunch, and go right to baling. Sometimes, it sets for 1 day.
We have had it pouring out while they were baling. Still, just fine, no problem curing & feeding. Did we lose some feed value??? Don't know, but by the condition of my cattle each year coming out of winter, I would say no - or at least not enough to affect wintering beef cattle (even some nursing ----- well, all mine are nursing if you consider the fact that we start calving in January LOL)