120v or 240v ballast option?

My magnetic ballast has the option to operate on 120 or 240 volts, however using multiple multimeters I'm consistently a 135 volt reading out of the sockets I'm going to use. Could be a bad neutral all together that the electrical company needs to replace, but would it be safe to operate the ballast on 120 volts when it's outputting 135?

Yes. It will be fine. I'm an electrician. Your service may not be balanced. Not really a big deal. I wouldn't worry about it.