In reply to crag_hopper_Jay:
You can also reshape the boot to fit your heels, (might be worth getting a ski boot fitter to do this)
Place boot in large plastic bag.
Place heel of boot (in bag) in a pan of water
Warm on stove to the point where the PU heel cup starts to soften
Remove from pan, stick foot in boot and pinch the heel cup to reshape
Hold till cool.
Disclaimer: get it too hot and the boot falls in bits (not good if it's a customers)