Ok, new data. Did some more measurement tonight. Measured my distilled water at 1.002. Made some sugar solutions, 1.109 (hydrometer), 26Bx (1.101). 1.073 (hydrometer), 18Bx (1.070). 1.040 (hydrometer), 9.6 Bx 1.037. So it seems to be spot on accurate. I used the long formula for my Bx...