After some fairly exhaustive testing I believe I have worked out that the mag range is actually 1.7x to 4.25x
& the digi mag is max 2.5x not 3.5x because it starts from 1 not from 0.
It certainly isn't anything like the 4x-28x mag range quoted in the specs, I've emailed CRS asking where the 4x-28x comes in to the equation,
I know that's from the manufacturer, but is rather misleading.
Anyway it's still a cracking good bit of kit, and highly recomended
Had an email reply from Ash at CRS, who says I'm pretty much spot on with the mag range.