A tire is a tire? LOL! Not true and each tire is designed differently. Bias Ply, racing slicks, Steel Belted, Multi Ply, Passenger Car, Light Truck, motorcycle, scooter are to name a few.
It is very important with scooters and motorcycles to ensure you have the correct pressure with the most footprint of the tire in contact with the road.
Example: Someone who weighs 105lbs would adjust the tire pressure to there weight compared to if a couple with a combined weight of 400lbs. would use a higher tire PSI.
Its never written on a tire what the tire PSI should be it just tells the MAX PSI and load weight for the tire.
This seems to be getting very technical with many different opinions I can only advise the way I check tire pressure to ensure I am getting the best performance from my tires.