So running around with my freshly re-tuned acrobat and came across something curious
With tier 5 acrobat adding +1 to crit range and multiplier.
A stout oak walking stick (not equiped to show standard) looks like this

So +1 crit range an multiplier should be 18-20 X4 right? Well here is what you get

and yes it does indeed crit on a 17. (sorry no SS)

checked my drow stick and tooltip shows 18-20 x3 but inventory screen shows 17-20x3 and that is correct from my observations.

Not that i'm complaining about swinging a 17-20 x4 but seems a bit broken