Interesting story. Fuel endurance and range assumptions are based on straight/level.
If I were showing even 5% higher, I’d be trying to get on the ground ASAP. When your tanks are that low, all it might take is turbulence (or a banked turn perhaps?) to disrupt the flow of fuel into the engine, causing fuel starvation.
During a turn, gravity might pull fuel away from engine inlet within the tank. If this happens, results might be catastrophic. Very happy to see that this airman was able to tell the story.