IBIN using lee dippers for so long I can't remember when I first acquired them...I have both the old and the new sets, plus I've made many home made dippers for specific pistol loads. I also have 6 different powder measures to boot.
As Mike said...they are and act just like any powder measure...they measure VOLUME more than weight...and you need to develope a technique for ANY of them to throw uniform charges.
My technique is to rap the handle against the stops at both ends...not hard just sharply...and use an aluminum wedge available or can be made which removes the weight of the powder column from the center of the powder cavity so the weight of the powder has less affect on the amount of powder filling the cavity. Not sure it really works but the theory is sound.
Even at that and depending on the bulk of the powder and size of the granuals, keeping within a couple of tenths consistently during a run is pretty routine...you just have to practice.
Mikana posted an excellent example.
FWIW going anal with powder weights except for the most exacting target work won't get you all that much...there are so many other areas to consider and put your time in on...I quit weighing powder charges a long time ago except for specific calibers and varmin/target/competition work...and then a slight variation in case volume will blow all that work out the tube...(pun intended

) If you don't weigh and measure everthing else to the "Nth" degree and your rifle isn't almost perfect to begin with, the only variation you will see in your targets is in your mind...no diss intended...I went through all this way back when.
BUT...that being said...I weigh my 17 FB, 17 Rem, 20 Practical and 222/223 cal charges, then trickle and get as close as possible...that is because small volume cases can get a bit touchy as far as pressure goes with a tenth or two difference when you're up close to the pressure wall and shooting in hot weather...and varmint/target accuracy can go south just as fast.
But it's all good practice and the knowledge gained is worth the time...
Luck