[css3-background] border-image-width numbers

In Backgrounds & Borders, we have this about basing the border-image-width on the border-width:

<number>
Numbers represent multiples of the corresponding border-width.[1]

Should we also say that if a number is used and the 'border-style' is 'none' or 'hidden', then the resulting border-image-width is zero? Or perhaps we should just say "Numbers represent multiples of the computed value of the corresponding border-width." I think that is the intent, right? So that layout geometry is the same in the fallback situation? 


[1] http://www.w3.org/TR/css3-background/#the-border-image-width