[Anjin]

The difference in measure thrust is due to different test articles and testing done in different labs. The 720 mN result was from China and they dumped a ton of energy into it. The smaller 20 μN result was from NASA's testing which used far less power, so the resulting thrust measure was also smaller.

[Niten]

You're incorrect, 20 μN was measured in the Dresden test at 700W.