Hi Vlad,
Yes you got me on this one: in our situation in 2017 I earned most of our income (around 120k gross) while my wife did various small jobs and tasks (at some point she had up to 3 employers) for around 500 - 1000 CHF / month. So although I may have correctly recorded all the AVS/First pillar and witholding tax for my salary, in the case of my wife her salary usually arrived waaaay before the many payslips; So in her case I may not have recorded all the social contributions. But the Net income is accurate in any case. The above exercice’s purpose was more to track our daily expenses after net salary.
Anyway, if you want to have a more precise idea of how much you will take home in your pocket, I advise you to follow the simulator, the picture may be more accurate than our special situation 