I have always been worried that in my fiction I tend to underwrite. Everyone I read about overwrites and then they cut, cut, cut. I felt I must be doing something wrong. Then recently I read a letter from a reader of Writing Magazine who worried about the same thing.So I was not alone after all!
I set off purposely to underwrite. I know my target and then write to between 10,000-15,000 less. I leave this margin because I know there will be stuff I haven't considered. I write quickly, sometimes extremely quickly and my aim is to get words on paper (sorry laptop). Later I will think about that piece and realise that the scene needs a bit of rounding, or in my haste I have left something not fully explained, even (like my current piece of writing) something I need to go back several chapters to check because I believe there is an inconsistency and I'll need to do a slight a re-write.
From this is sounds as if all I do is add, but that's not true. I do cut as well. I've cut nearly 1,000 words at a time if something isn't working. However, the underwriting is something I worked out for myself and only worried about when I began reading how other author's work. I also see my underwriting target as a slightly easier goal. But editing is something else. Like with poetry it is hard to know when to stop! I will do anything to avoid the process, partly because I get fed up with looking at the same manuscript. I don't find it as creative. I want to be telling new stories. And so I do, When an idea forms I start writing and I fall in love with it, abandoning my edits on a previous work. Yet, some time away helps and I know I must return to my first novel and get it finished ready to submit. By the time it's fully edited it will be overwritten!
The reader's query, which so worried her, was advised that underwriting was okay if she was a spluger (like me). So, I'd say it doesn't matter which way you write. Go with what works for you as long as you get the desired result. Reading about how author's work is interesting. I learn a lot and sometimes it's good to know what I am doing is very similar, but in the end writing is a creative process and nothing should stand in the way of that even if it is different from the way most author's work.