Being a creator I'm at liberty, at anytime, to change the script. Which is good in my case as I never start drawing with a complete and concrete script. My process is one that goes back and forth. I have all the dialogue and action down but I don't have the pacing. I work out the pacing as I thumbnail. I have rough page breaks but with all the mucking around I do I can go from 40 pages to 48 or to 36. I constantly edit and revise the action. I hope I get a better product because of this.
Here is an example of some pages of script that I mucked about with.
The above sequence was edited down into the page below and then changed some more. More changes are likely to occur as I draw these pages. What works in a thumbnail doesn't always transfer to the page. Also as I write for myself and I know what's going on, to save time I write the barest directions.