I've been doing quite a lot of ladder testing lately and my rounds tend to go low left with light loads and walk to high right as the powder charge is increased. The same has been true regardless of powder tested.
I have not seen a case where an increase in powder charge reverses this reality, but more high right randomness does occur when loads get really hot.
I have seen where certain powder charges cluster in one place on the target and others do not.
Charges that string, tend to do it along that same low left to high right line, but not necessarily in strict accordance with exact speed.
So bottom line to me is just find a load that clusters, wherever that is and do not ignore left to right in that assessment.
I mean seriously... why would anyone ignore valid data? You cant cherry pick only the information that conforms to some article you read on the internet. Just use common sense.