I understand from your previous thread you want to change because your finger pricks are consistently lower than your HbA1c. There are many reasons why this happens - you are by no means the only one on this forum. I am one of them, too. The HbA1c has many flaws, one of which is you have to have average standard red blood cells that live for an average standard time of about 120 days. Longer than this and your HbA1c will be elevated. Shorter than this and it will be falsely low. As we have no idea how long our own RBCs live, and no way of finding out, we are stuck in a one size fits all scenario. I have had to accept several years worth of HbA1cs that are higher than expected. I understand how annoying it is, but now I just look on that test as something to keep my nurse happy. My finger pricks, a home A1c and an occasional Libre keep me happy.
For clarity, I use an Accu Chek Mobile, which I find excellent although with expensive cassette strips. (half price on eBay)