When I had my van weighed they gave me 3 figures. Total weight, front axle and rear axle. All were within the limit (just).
My tank is set back a bit from the bulkhead so it is more central. If it had been against the bulkhead I think my front axle would have been overloaded.
Those who have tanks against the bulkhead, especially upright tanks, could well be overloaded on the front axle.