Certain units, for example the new Tzeentch tzaangor can wield a pair of weapons, in their case paired savage blades. This generally comes with an additonal rule (e.g. re-roll 1's). Is this bonus rule all that they paired weapons give or do you also get to attack twice as much with the weapon? The phrasing on them isn't Always clear if it would or not.
Have you got the wording as although you may think it is unclear most of the time it is clear you just have to read it over and over.