That's fairly non-standard with 182s...
Usually they're kept filled "to the tabs" or something similar so fuel vs. payload can be managed.
Does the 182 have l/r tanks? That'd make that rule painful.
Filling them up is a good way to lose a lot of the airplane's utility. Especially if they're "restart" aircraft which have so much crap on board they've lost a lot of load-carrying capability.
If its a "legacy" 182 does it have a 2950 Max Gross?
Many have an STC available to raise t/o weight to 3100. Restarts are 3100 MGTOW with a 2950 landing weight.
Ours does have the STC available and we're still debating. It's ~$700. Roughly $5/lb for a 150 lb. increase. Not sure if it's worth it.
We have l/r bladders and full of fuel, it's longer-legged than most people are comfortable flying in one leg. We keep in touch and if someone's planning on a big load we don't top it off.
79 gallons is a lot of fuel. 6 hours without any reserves at 13 g/hr.
At this altitude we rarely see more than 11 g/hr average. At sea-level, higher for t/o and climb and 13 in the lower altitudes.
Our 182 with 4 hours of fuel on board for 3 flight hours with an hour reserve is quite a good weight/butt hauler. Her useful load is 1134 lbs without the STC. 4 hours fuel makes 822 lbs useful load. Full fuel useful load is 654 lbs.
With the STC she'd haul 1284 lbs of fuel and butts aloft. That'd be 972 with four hours fuel and the STC and a whopping 804 full of fuel with the STC.
Few Skyhawks can get close to that. A Skyhawk can beat her, but can't fly 5 hours and land with an hour remaining at the same time.
That full tanks rule is a PITA.