Most of my writing time goes into the first four or five pages.Even if you consider all of the plotting and pre-planning a different thing, it is still those first few pages that take the longest. I don't know why that is, it just takes a long time to get started.
Through the middle section it starts to pick up the pace. It isn't that those pages are easier, they just move a little more quickly.
Then, almost every time, I find myself suddenly at the last few pages. These pages move so quickly that I get worried about being able to wrap up the issue in my allotted 22 pages.
Right now I am in that home stretch. I have a certain chunk of story to tell, and only a certain amount of pages in which to do it. It looks like it will work, but I will have to make some tight decisions.
That will be issue 25, likely done ahead of schedule. It is the start of a whole new story and I think it is coming out pretty well.