SMS messages are charged per ‘segment,’ and the cost increases if a message exceeds 1 segment. The text you sent likely exceeded this limit, resulting in multiple segments being used.
This is similar to how SMS functioned in the past when messages needed to remain within a certain character limit. While modern devices make this less noticeable, the underlying carrier billing structure remains the same, with charges applying based on the number of segments used.
If you are doing bulk messaging you can use this to find out how many segs you are using - SEGS CALCULATOR
