Well done Dusty,
I was unaware of the Swift study, But I'm please to see the subject has been looked at by a manufacture.
Let me state now I have no doubt that Swift has the evidence to support the findings of this study, the snippet of teh results does not actually tell us very much, and I suspect that most caravanners would not see anything like the efficiency savings Swift suggest.
For a start The report is not comparing a new swift with and older model swift, but an unnamed competitors model. I would presume the model chosen for the comparison would be most likely to emphasise the differences. We also do not know if the competitors model was a current or really old design. So by removing makes and model identifiers in this short report prevents any meaningful conclusions to be drawn by readers.
The testing has been carried out under Lab conditions, and simulations, so this is considering ideal conditions. Now fundamentally this is the way to derive repeatable and verifiable data, and the results should believable. Unfortunately real life conditions are highly variable. I looked for evidence of real life road tests in the report but I found none, So I am sceptical about the scale of the claimed benefits being repeatable in real life."
However one sentence did catch my eye, and is relevant to this thread.
"Again, the results were surprising with the smaller features not having as great an impact as first thought."
Bearing in mind the report is about towing efficiencies rather than stability, its still likely the underlying meaning of teh quote holds true in relation of stuck on tabs affecting stability.
More validateable evidence please Swift.