Ls vs. Sol values

We have used a sol-based visualization instead of Ls based one. Here is why:
Below is the data for N70 and S70, above in sol based, below Ls based x axe. If you look at the sol based diagram, you can see larger difference: longer summer in the north, shorter in the south. The Ls based diagram obscures this difference. (However, the diffrence is not very large)