I'm pretty sure that longer messages still generate multiple "packets" or whatever you want to call them on the backend. Which is important if you're paying per packet. It's just that every modern phone knows how to collect and stitch them together into a single displayed message. That's why phones still display the number of messages being generated when you type in longer ones. For instance, mine starts showing "10/1", then after another character "9/1", eventually to "0/1" and then "145/2".