Just looked into your boot, a boot for junior racer as well as women. I remembered looked into this, but the higher number of flex deterred me. If I ever get into the expert range....
Heck, I am no expert. I am very very intermediate (intermediate to the square root of 2!)
There are 2 pins in the back of my boots. Having both pins in make it "stiff".
Removing 1 pin make it less stiff (more flex), removing 2 pins make it very flex. My boot fitter removed 1 pin and I am able to fiex my ankle without feeling too "stiff".
I was told by my boot fitter: You can make stiff boot less stiff, but not the other way around.
Found more notes from my boot fitter friend to share. This is about the order of buckling your boots and how to make your heels sit in the back of boots.
"As your foot moves about in the boot a pocket will develop over your cuneiforms this will usualy relieve pressure over the arch.
Remember to only use light pressure when buckling the toe and instep buckles over your foot, I recommend One finger pressure.
You can adjust by spinning the buckle left(loose) or right(tight) and adusting bail position to get this pressure.
Remember when you put the boots on to always buckle the top cuff buckle and tighten the powerstrap, then flex at least 5 times.
this will lever your heel back into the pocket.
Then buckle the lower cuff buckle and flex again tightening both cuff buckles until you have firm presure around your calf and your heel is
locked into the pocket of the boot.
Only then whould you attempt to adjust the buckles for the toe and over the instep.
Remember, these boots are not buckets and your foot should be restrained in side to side motion by the tight fit.
If this condition does not go away your fitter can adjust the boots to remedy this condition.
It's a very easy fix most of the time especially on Lange Race boots."