If a aircraft manufacturer states that the MTOW is 225,000 kg in it manual.
and a Regulator (FAA/CAA/CASA) states that a flight shall not be planned to take-off above MTOW.
And the Regulator has approved the company operations manual to plan a flight.
The Regulator will over rule the manufacturer in every country.
So if approved, that unused but planned taxi fuel weight need not be deemed excessive then that aircraft can legally fly above the manufactures listed limit - in this case it can take off at 225,500kg.
Key word/s are planned & deemed excessive - excessive should be described in the company approved manual.