Define flex please?
My thinking board is like a spring, ie. a pen spring. Does a spring fly in the air when bent and released?
Same with a board. But, your corecell hasn't got any elasticity and that is a problem. My bamboo board is like a spring. The elasticity of my board will slingshot you in the air like a soft snowboard.
I am 59kg dry, for sure a springy board for a 100kg rider should be a quite different elasticity.
Do what Plummet suggested only if you didn't varnish your board. If you did, too bad. Epoxy won't bond any more.
It would be interesting to know more about wobbly and high elastic boards. Modulos of elasticity are different for every material and I do think more elastic boards are better for big air. Also more forgiving for a knees and ankles.
If the biggest air is with a stiff board, fair enough. But can one one be sure if never tried an elastic board in the same conditions? Plummet?
Just my 2c.