The latency test means you create a click or other rhythm track and then play that in overdubbing with your headphones jammed against the microphone. The latency correction is the difference between the two tracks. Has your microphone ever worked with the new system?
Audacity has no official videos and we’re not fans of YouTube publications. Most of the existing ones are out of date, misleading or just wrong.
People post instructions and then lose interest when they find they have to submit to the Audacity Editorial Process. It’s not fun having a company tell you your video is wrong. So they leave the video up there, errors and all.
If I understand correctly, the latency issue should remain corrected now.
Recording Latency can change if you do silly things like fill up the computer, change drives, etc. Hard drives can slow down as they fill up and external drives (USB, FireWire, Thunderbolt, etc) are not recommended because their latency can change minute to minute.
Internal spinning metal is fine, Solid State much better.