As with any powder measure, you must use a consistent charge to charge routine to get consistent results.
I have used a Little Dandy for pistol charges for many years, with good results with a wide variety of charge weights and powders.
I keep topping off the reservoir to keep the powder level within the upper one inch of the tube.
I turn the rotor, tap three times on the side of the rotor to settle the powder in the rotor, then turn it, tap once to make sure all powder comes out, then repeat the sequence with the next case.
I am anal about consistent charges and weigh-check frequently and have always been satisfied with the results. You develop a ritual or routine kind of like a baseball player's approach to approaching the plate and swinging on the ball.
olevern