Guild Wars 2

I was curious as to why items list 2 sets of the same stat with different numeric values. For instance one back piece I was looking at has the prec, tough, condition damage stats listed and then lists them a second time with different values.
Ex. http://wiki.guildwars2.com/wiki/Tome_of_the_Rubicon

Also some ascended items I saw list the same thing but the bottom set of stats are grayed out.

What does it all mean?

the ascended items have 2 sets of stats because they have the base stats and then they have the stats equivilent of an upgrade item in other items.

For example the Tome of the Rubicon, first stats are the Rabid stats the item has as base, then the second lot are the equivalent of a rabid crest slotted into it.

For the greyed out stuff, I’ve never seen it so I couldn’t say.