IMessage sending as SMS even though SMS is off I am hitting "try again" instead of "send as SMS"

Question

This is a problem that has only started happening in the last month or few weeks.
1.  I have "turn sms off" in settings.
2.  This happens with people who I know have iPhones with whom I iMessage regularly.
3.  When the network connection is poor, and I attempt to send an iMessage, I get the exclamation mark.  Before the last month or so, I would hit the exclamation mark and choose "try again" and if the connection is better, it would go as an iMessage, or if not, it will give me an exclamation mark again.
4.  In the last month or so, when I hit "try again" it doesn't try again and will just go as a SMS automatically, even when I am back in a good network connection spot. 
5.  I have neither changed equipment nor networks in the last year.  
I find this to be highly misleading and problematic.  Is this a bug that just started recently? 
Does anyone know what is going on or how to prevent the iMessage from going as SMS?  I understand how to iMessage instead of SMS'ing so please responding about the basics is not helpful.  Thanks!

Answer 1

All that does is keep it from falling back to SMS if an iMessage fails to go through.
If the individual you're messaging isn't an iPhone user or has iMessage disabled, it will always go as a normal SMS message.