I94 in B2 extension

I just applied for my parents extension and got approved. haven't received the letter yet. but want to tell something about I94.
when I applied for extension, I searched in here and everyone says you have to send the original I94 card with the application form. I search in another immigration website again, it says copies of I94 are ok now. if you send the original I94 by mistake, then you have to file some form to get them back. so I decided to use tthe copy of I_94 and it works.