but it's your choice if you want to add the entire sequential note but AZ suggested that you don't as it provides no value but in my opinion it provides value.
As far as keeping track on issued serial number ranges, there is no value in doing this whatsoever. It is easy to enter all notes from the range and the count of your notes in the database can grow much faster, but it is essentially cheating.
And yes, when you enter first and last note from a range, only 2 notes are added to the database and the total count of your notes increases by 2, as expected.