Stamina issue - VAIO PRO 13

Dear all,

I do have an issue with the stamina.

After formatting my VAIO PRO 13 (SVP131ACM), I do have a maximum stamina of 3h30 instead of the 5h30 I do have before formatting...

I have installed all previous drivers etc but I doesn't change anything.

I have tried to press the small button on the bottom on the laptop but problem still exist..

Any idea how I can recover my old stamina ?