Thank you for making such a good comparing test!
Lightning cable test is complicated. The main reason is because there is an Apple certified chip inside of the head. The chip controls a MOSFET switch to turn on/off the power on the power wire in the cable. You have to communicate with the chip first in order to pass it’s verification. There will be no power on the wire otherwise.
In your case, I would say the black cables might not be real Apple certified Lightning cables. That’s my guess.
The basic version has different mechanism then X version to turn on the power on the power wire. Basic version uses a chip(hardware) to communicate, and the X version uses software. So there might be chances that the basic version could be able to turn on the power on the power wire while the X version couldn’t.
We have made a lot tests with all kinds of cables. Your case is rare. You are the only guy who has reported this issue so far. I would say the results you’ve got from the qualMeter Basic version is trustable on the charging capability. However, I would say that 2 black cables might not be real Apple certified cables.
Thanks again for your testing and I would love to discuss further issues with you to improve our products.