No it’s not wrong because OL says a margin of +,- 2mm. In the other side we can change those numbers with out any negative consequence because 225 means longer EL and les distortion.
This is poor advice.
The OP expressed the desire to use an Arc Protractor.
Anyone who professes to be an expert in tonearm set up would know that an arc protractor is designed for a given mounting distance and you’re not supposed to use an arc protractor designed for a given mounting distance with another mounting distance.
If you are going to use an arc protractor, the mounting distance must be absolutely spot on.