L is for first 2 gears only, it does not shift to higher gears
S is for 1, 2 and 3rd gear.
I used both L and S while climbing and decending from Motorway at Kalarkahar Point.
Putting L increases engine braking and I used it while coming down from Kalam and when the road got better (less decline) I shifted to S and then when the road got normal I shifted to D.
So you need L and S gear seriously and had I been using only the D gear then I would have been using (heavy usage) of brakes (braking).
You can't do without L and S.
In Yaris 1.5 which we also have, you just have D and then triptronic . There is + sign and - sign you can use lower gears or higher gears accordingly.
But City CVT gearing reduces this tension, so it is better than Yaris in this point. Also the rear seats have lots more leg room than yaris and they are a bit more wider in the rear. My family had failed yaris on sitting in the back so that's why i choose city even though it is more expensive and around 40 kg heavier than the yaris 1.3 (1.2 city weight).
