I have 3 blood pressure checks on three different machines. First one would inflate, deflate, inflate deflate to give an odd answer. 2nd one dos the same thing and wouldn't give a pressure.the bourse said, it thinks it should be higher. The 3rd was a wrist cuff and an abnormally high pressure for me. Are the computerized machines programmed some way to compare the size of the arm to pressures in that area according to weight?