DS-156一定要用最后生成的那份吗?

I filled online, click continue and get a pfd file. I saved it as file1. then I filled another one online, just to add NA to some of the questions, and get another file and saved it as file2. But after consulting people here, I was told NA is not necessary. So I sent to my parents file1. But I read all the comments here, seems I must submit to VO the last file generated. Is that true?