Every trip we take, whether by car, rail, boat or plane, exposes us to risk.
Not accepting 98 octane mogas because you were told to only use 95 octane makes no sense and I suggest using the 98 would add zero extra risk.
However, travelling 230 km extra distance to get another fuel has a definite extra risk.
I am not a mechanical or aviation expert but this is/or should be risk assessment 101.