Hi williamturner1

You might be reading off the wrong rows.

I've compared the 2 shape:
'I beam' width 100mm, depth 200mm, flange 10mm, web 7mm
RHS width 120mm, depth 80mm, wall 3mm

Assuming length 2000mm, and your weight 60kg, and vertical Z deflections are:
I beam 23 microns
RHS 393 microns

Which tallies with your jumping experiment, showing the vertical stiffness difference, where the I beam is much stiffer.

Unless you had a lever arm to jump on (which was very stiff), then you would not be comparing the torsional performance which I would expect to be worse for the I beam.