Neverhome:
The check weights in the link are precision and are marked as to their actual weight. Buy them, and then use them on the two scales. That will determine which is correct.
If I were to guess, and I will, the LEE scale is probably off. Just because it is mechanical does not mean it is accurate. LEE must fear over loads as their scoops and the chart that calibrates them to grains of powder typically are always light on powder. I'll beat the drum again: LEE stuff is not of the same quality as virtually all the name brand equivalent equipment. But it is cheaper... The "Harbor Freight" tools of reloading. If cheap is important to you then use it. Otherwise skip them.
In general electronic scales are touchy to use. They can drift over time, loosing their zero and falling out of calibration. I use a Dillon scale (a 15+ year old version) and I am constantly zeroing it (before every measurement!). I check it against the checking weight set in the link occasionally but find it not more than 0.1 grains off at almost any load level. I turn it on an hour before I start using it to get it to settle into a good zero. I make sure there are no wind currents in the reloading room and it is plugged into the wall for power (no battery operation). I also have the top of the line RCBS mechanical scale that I have not used in 15 years. I much prefer the electronic scale. The mechanical scale endlessly swings back and forth, making measurement a long time thing. I'll take the electronic scale every time.
LDBennett