On the jobs where you need system design, a PE that had experience, in fire system design, is fine.

We just had to fire a customer, they decided to hire handymen to do building upgrades, these guys had no idea what they were doing but they had a tool box and a truck with a sign, we started to receive trouble signels and flase alarm signals, we called the building, and they said the alarms were just going off, what it turned out to be was this bozo they had doing the work was related to one of the people working there, so they were protecting his distruction of the fire system, after a few calls someone said oh we are having work done here, but would not allow us in to check, so we called the AHJ and fired the customer, we were not about to take on the liability for some bozo handyman, that was taking apart smokes, and moving them.

When AHJ finally inspected the site he found other fire violations, boxo was replacing fire rated doors with non fire rated doors.

So be carefull when chosing your accounts, and with fire your job does not end when the install is complete, it continues, you are married to fire jobs.