Fuel Gauge readings inaccurate, need help recalibrating...?

[Joby]

Hello,
The spec for my 2024 Solara shows a 116 gal fuel tank. We have physically verified this by inspecting the factory stamp on the tank.

Both the Garmin and the Yamaha CL5 are in 'synch' - showing the same amount 'remaining' in terms of percentage. And they both show a 116 gal tank installed.

Refuel stop number 1: gauges show 35% remaining, yet she takes 96 gallons to fill. Refuel stop 2 : gauges show 47% remaining, but she takes 79 gallons.

(Stating the obvious)This error is working against us; showing much more fuel than what's actually there. If one (incorretly) assumes the entire 116 gal is 'useable', then by the math above, these gauges think it's more like a 135 gallon tank. But I am having to subtract way more than the 'Industry standard' 10% for 'unusable' fuel capacity.

I look forward to your comments and suggestions on what is going on here. If there's a factory rep reading, kindly let us know what is the 'usable' fuel of the 116gal tank on the vessel. Feels like the calibration just completely off. Gosh I hope I've made a dumb newbie error. 🙂

thanks in advance,
-Joby