Netherlands: Can you save money with CV-ketel + electric boiler in combination with hourly energy prices?

In the Netherlands most people heat both their house and tap water with gas. I was wondering: could you save money if you install an electric boiler before the heater and only heat it when the electricity price is relative to the gas price low enough? If not, you heat water with gas.

This could be interesting when the electricity price is low and the gas price is high. The table below calculate the effect for many combinations of prices.

The formulas (and the assumptions) I copied from this webpage:
Boiler kosten: berekenen – Boiler-info.nl.

Assumptions
• Energy depend per person per day is 2,5 kWh.
• If you heat with gas it would be 2,5 kWh : 8,53 kWh = 0,29 m³.
• Daily cost Electric would be 38 ct
• Daily cost gas would be 44 ct
• On yearly bases this would save 208 EURO a year
• This assumes that every day you can heat water for 15ct for KwH

What do you think about the assumptions and the calculations?

example: installing boiler before heater: see paragraph 5.2.1
https://www.intergas-verwarming.nl/app/uploads/2018/01/Installatievoorschrift-Kombi-Kompakt-HRE-88557803.pdf