Yeah, I hear ya on that one. I write on the seat of my pants too. I didn't do my profile until after Peterson Estate was written a few years earlier. I decided since I was rewriting the book from memory, I would get to know my characters a little more even though I already felt like I knew them lol. So it came to be a lot easier for me at that time.
The profile I used came from a website on characters. I can't remember the site's name now because its been so long--mid 90s lol. I ended up making my own profile based on that original one which helped me better because some of the questions that were listed didn't really work for my book. I think each writer should create their own as well so that they work with their own books. And sometimes, they can be filled out while you're writing that book which works too.
And profiling doesn't have to be done all the time. It is a simple excercise that teaches writers how to be self aware of our characters. If you can do it mentally, all the power to you as a writer because it means you're growing as a writer!