Hi Miguel,
That's correct. The line count is the amount of records retrieved by the aggregate and brought back to the client. The platform decides how many to retrieve based on many things, for example the line count of the widget(s) displaying the list.
You don't have to worry about this difference. They probably use it as a way of knowing if more record are available in the database and what the next record is.
Is this causing any problems for you, or is this just out of curiousity ?
Dorine