So what if there are a few typos in your script?
Why get so anal about it? I will tell you why. Number one, it interrupts your story. Number two, it makes you look unprofessional.
Imagine you're walking along a verdant hiking trail. The sun is shining. You can feel it’s warmth on your skin. A slight breeze is blowing. Suddenly, someone runs past you wearing the most obnoxious colored running shoes. You laugh to yourself. Then, you notice a grey squirrel run up a tree, trip over a tree root and fall flat on your face. That is what it's ike when someone reading your script comes upon a typo. Your are reading along, getting into the emotion and action of the story...and then you have to stop to figure out what the writer really meant. Bottom line: It takes you out of the story. You try to figure it out, or hope you figure out correctly what the writer meant, and then continue on…until the next typo.
This profession is tough enough. You want to give yourself every advantage. Help your reader, if you are lucky enough to get someone to read your script, to stay in your story.
There's a thing called "spell check." As such, it amazes me how many typos I still come across, even in synopses and pitches. You're a writer; words are the tools of your trade. You should know the difference between "your" & "you’re"; "there" & "their" and "it’s" & "its." Look, I know it’s tough, you read your own script so many times it’s easy to gloss over certain passages. So have your mom, husband, wife, best friend, or a total stranger read your script for typos.
If not, you risk loosing your reader. Spelling intended.