[Theory] Pokemon's Gravity?

So, here's the sitch. I'm working on a theory video regarding the Pokemon world's gravity, because there are bunches and bunches of Pokemon who, when you put their weight into grams and then calculate density based on volume, really don't weigh what they should. Onix weighs less than 500 pounds, a weight that it shares with some real-world humans, yet is far more massive than any human and is made of stone, which is far denser than any human, making it theoretically even more massive. Steelix is even MORE massive, seeing as it's twice as heavy as Onix without being that much bigger, giving it a higher density. And let's not even get STARTED on Wailord, who, if we're to believe the weight we're given in the Pokedex, is less dense than water. So much so that it if it were in a large body of water, it would just bob around at the top like a piece of styrofoam. That just can't work for a Pokemon that's said to be capable of diving 10,000 feet underwater, so my theory is that Wailord is able to sink in water because it's more dense than water, gravity is just weaker in Pokemon so it weighs less.

I want to figure out what the gravitational force in the Pokemon world is using the weight of a Wailord, but I'm terrible at math.

A Wailord weighs about 400 kg and is close to 50 feet long. The closest comparison is a female North Pacific Right Whale, which averages at a 49 ft. length (Which we'll round to 50) and about 50-80 thousand kilograms, which we'll average to about 65,000 kilograms. So, theoretically, in the real world, a Wailord would have 65,000 kilograms of mass to it. We'll transfer this into a weight-specific metric, because mass doesn't change no matter where you are, and get around 143,000 pounds, with a Pokemon-world Wailord weighing around 880.

So, my question is: In order to have something that weighs 143,000 pounds on earth weigh 880 pounds somewhere else, what would the gravitational force in the Pokemon world be?