If you just got the meter, why do you suspect that it's off???
I had a 358 for several years, then replaced it with a 558 to get the spot capability.
I found both of them to be right on. Sekonic meters are accurately calibrated at the factory.
Proper exposure has a lot to do with your shooting and processing habits.
If the meter doesn't produce what you want after a lot of experimentation, then adjust it.