Her is a quote from a tasting session, giving the composition of the whisky:
What's in it?

5% Caol Ila refill casks - American bourbon barrels
12% Laphroaig refill casks - American bourbon barrels
17% Bunnahabhain American sherry
9% Bunnahabhain refill casks - American bourbon barrels
26% Highland Park - Spanish Sherry butts
14% Highland Park - American hogsheads
9% Ledaig refill casks - American bourbon barrels
8% Bowmore refill casks - American bourbon barre

It appears here that the refill casks have already been used for Bourbon.

--------------------------------------------------
Note added at 1 day2 mins (2006-10-26 09:41:40 GMT)
--------------------------------------------------

and here's another quote:
The vast majority of casks filled were known as ‘refill’. In other words they had previously held whisky, had been emptied following maturation, repaired where necessary, and sent back for refilling to a distillery. The bourbon, sherry, port or rum casks only merited that descriptor for their first filling with whisky—thereafter, on emptying, they would become refill casks. You can find this on the following website:http://www.lfw.co.uk/whisky_review/SWR17/article17-3.html

--------------------------------------------------
Note added at 1 day1 hr (2006-10-26 11:35:00 GMT)
--------------------------------------------------

I withdraw the heading to my answer - your text is not inaccurate! It makes the distinction between "first-fill" and "refill" casks. All have been recycled, or used before, but the "first -fill" have been used for sherry or bourbon whisky, whereas the "refill" have been used for Scotch whisky.
I think this sums it up nicely : "A refill is any cask which has been used for maturing Scotch whisky more than once. In other words, any cask which is not a ‘first fill’ cask. Refills are much less active than first-fills"
http://www.whiskymag.com/magazine/issue11/12005043.html