I had to make beans for my favorite 9 year olds' school for Pioneer Days. For 60 kids as a side dish, I thought five pounds seemed about right. Of course, it was about twice as much as I needed but again, I learned a little something.
I thought it would be fun to document the soaking process. I know, fun should include drinks and boarding passes, but I make do using what I have.
So this is five pounds of pintos in plain water:
During the next check in:
And finally, before cooking:
I'm not sure what the point of this is except that I'd read that most of the absorption of water happens in the first two hours. This may be but as you can see, the last hour was almost equal to the first two. I feel comfortable saying 3-4 hours for beans that have been harvested within two years is a good guideline.
What difference does it make soaking or just cooking? Well, I really think the texture of soaked beans is superior and there are fewer surprises. You probably won't have to add much, if any, water while cooking and you have a better idea of your yield. If I hadn't soaked, I'd still just go ahead and cook them without a soak.
The volume you were cooking may have benefited from soaking texture wise and cooking time wise. However, remembering your statements favoring no soak method seem a bit confusing in view of what you say here.
90% of the time, I don’t bother soaking. I think the real message is soak if you want to. Salt if you want to. Slow cooker or IP if you want. In the end, beans are easy to cook and as long as you’re cooking them, there are not many absolutes.