This result can be compared with simulation were I assumed for now same retardance vs voltage and extinction ratio equals to 1.

The rotation and retardation are shown in figures 1 and 2.

The retardation agrees really well with measurement if we wrap the measured retardation to positive values (fig 3).

Forthe rotation, it seems we have some kind of 90deg offset. I'm wondering if it could be because the first LC is rotated by -45deg instead of +45deg.