I have rediscovered something else: available time to write does not directly translate into wordcount.
If I'm writing dialogue or description, but most especially dialogue, the words pile up faster. Word acquisition slows when I'm making subtle changes, or changes in many places.
I think there are a couple of reasons for subtle changes being slower. One is that I spend time scrolling or searching around in the document for the things I need to change. The other is that each change requires time to think, and if the changes aren't related to one another, each one requires a little thinking time of its own.
If I'm just adding in a scene, I can start at the beginning and proceed to the end, or an end; also, I've usually thought about what I'm going to do in that scene before I sit down, so it's just drafting, or if I'm really lucky, transcribing.
Why do I ponder these questions? Well, I feel better about my writing if I feel in control of it. It's not something one can control in every aspect, but knowing how I work, and that my methods have been successful in the past, is reassuring. Understanding my process makes me feel more in control of my process.