ARB Stiffness Sanity Check Measurements

I am measuring antiroll bar stiffness for the first time. Although it is pretty straight forward, due to limitations of working in my own garage I've had some difficulty. I am limited in an anchor point. I'm working off a quick jack and the best I could do was use a ratchet strap to pull the sway bar up with the anchor end attached to a bracket inside the car (through the strut top hat mount). I can only get about 100 Kg of force on the bracket before it starts to deflect. Ultimately I'm just hoping someone can tell me from their experience if these numbers look roughly correct given the limited sample size:

The measurements are for a 22mm rear sway bar on a 2011 Subaru STI. See attached picture.

That's pretty much as I would expect, with the non-linearity probably being down to the angle the force was applied through changing.

Thank you. I ended up remeasuring a few times and was able to get repeatable results. Thanks for the sanity check!