If your journeys are only about half or a little over of the total possible range, it is worth cutting the charge at the point the fifth LED comes on since this will avoid the charge extremes, full and empty, both of which stress the cells the most.
If cutting that top 20% of charge means you have to use the battery to almost empty, you won't gain anything and may even lose out a bit.
Also bear in mind that in the long term range declines with cell age, so what is ok now may not be in 18 months time when the range may leave you emptying the 80% charged battery each trip.
.