lineid keeps incrementing even if you delete lines. The behavior definitely changed in 2018.1. If you have 2 lines and then insert a new one in between them, the original line 2 will keep it's lineid of 2, the line sequence number will be 3 and the lineid of the inserted line will be 3. We used to have a custom column that sourced {line} which showed the equivalent of line sequence number. That broke now and I actually had to write a before submit user event to populate the column. Our reps like having line numbers on printouts.