Is it possible that the OP is looking at recipes for SCOTCH ale? isn't that a somewhat popular belgian style? which might indeed have candi sugar in it.
Scotch Ale is not a belgian style. It's in the same grouping (Scottish and Irish Ale) as the Scottish 60/- 70/- etc. Scotch Ale is also referred to as a "Wee Heavy".
Now that I think of it, the Belgians do
make a Scotch Ale-- McChouffe (and I only remembered that because I saw bottles of it yesterday in a liquor store).
I don't know their formula (except that they do use Belgian yeast) but I guess it wouldn't be too much of a stretch to think there may
be some candy sugar in there. I've seen it described in more than one place as a "Scotch Abbey Ale" (which itself sounds intriguing). I'm not very big on Belgian beers at all , but I intend to pick up a McChouffe this week and give it a whirl.
But if you're looking at a more traditional or 'authentic' (whatever that
is) Scottish or Scotch Ale you probably don't want any sugar in there (nor would you want smoked malt of any kind).
But in the end it does really come back around to "whatever works".
The end result is generally more important than how you achieve it.