Could IOS7 iMessage be sending SMS?

[Sierra]

Just reviewed my Verizon bill and since I don't have texting (not worth the the $10.00 and 90% of my clients use iPhones) I noticed I got billed for 11 incoming text messages but no outgoing. I did converse with someone recently but all iMessage.

Is there something in IOS7 on the other user's phone that used SMS? I have IOS 6.1.2 and disabled SMS for my outgoing iMessages.

 

[willerz2]

It might be that the other person does not have iMessages turned on, or they do not have internet access while attempting to send you an iMessage, so it comes through as an SMS if the user toggled on "Send as SMS" if the iMessage does not go through

 

[Sierra]

If the other person has it off, then I would think it would not show up as iMessage on my end. Also doesn't a data connection (not WiFi) work for iMessage?