Is $300 to troubleshoot a Hoymile HM-1200-NT microinverter a fair price?

I've had my solar setup for about 2.5 years. Around two weeks ago, I noticed that two of my 21 panels stopped producing power and haven't resumed since. While I can still see voltage readings in the Hoymiles app, there's no current or power output from those panels. These two panels are connected to ports 3 and 4 of the same microinverter. Interestingly, the panels on ports 1 and 2 of that same inverter are still functioning normally. I'm questioning if this could indicate a failure in one of the MPPT channels of the microinverter. The cost of the troubleshooting visit is nearly equivalent to three-five years' worth of energy production from those two panels, which makes the cost hard to justify without more certainty. I actually just got off the phone with Hoymiles. The guy I talked to was super helpful. He looked up my plant and brought the alarm code up, and said, "Just as I thought, error 308." He said he was going to do a firmware upgrade on it and give it 48 hours to see if it fixes itself. If not, I can call back in and they will send me a new one to my address to swap out myself, and saving me $300+ to have a company come do it. So far I'm thrilled with the response by them.