Normally I would say when the car's is mapped for XXX Ron, you MUST use that and nothing else, at least nothing lower. It could damage the engine severely when it's starts knocking at wot.
The only exception is when the car has a very good knock detection system, which would allow the use of fuels with different Ron. But if it hasn't got that standard, then it doesn't have it when remapped.
Otherwise, either use 97 Ron or better or get it remapped for Ron 95.