If its a PRI the only time you would need to regenerate the config is if you changed the number of channels. But I have also found the 3cx generated configuration always configures it for 23 channels regardless of how many I set in 3cx. So I always manually modify that. Once I have uploaded the config and changed the channels I never have to touch the patton again. You can add and modify DID's and caller ID and what not without having to upload to the patton. If this is an analog gateway and you added or removed lines is the only time I would think you need to upload a new configuration.