Q:

Naming tetrahalogenated benzene

ChemSketch generates the IUPAC name of the compound above as "2-bromo-1-chloro-5-fluoro-3-iodobenzene" but I have a different answer. 
I know that I have asked a related question before as well. The key takeaway from orthocresol's answer was that:

first, order the prefixes by alphabetical order, and then choose the locant set in order to minimise the locants

I have applied the same here: the prefixes ordered in alphabetical order are "bromo, chloro, fluoro, iodo". Now, I have to choose a locant set that minimizes the locants. A possible locant set is "1-bromo-2-chloro-4-fluoro-6-iodo" which correctly locates the substituents. Also, the locant set "1246" is lower than "2153", as noted in this answer. So, according to me, the preferred IUPAC name should be "1-bromo-2-chloro-4-fluoro-6-iodobenzene".
What exactly am I doing wrong here?

A:

The locant set ‘1,2,4,6’ is not lower than ‘2,1,5,3’.
According to the current version of Nomenclature of Organic Chemistry – IUPAC Recommendations and Preferred Names 2013 (Blue Book), the lowest locant set is defined as follows:

P-14.3.5 Lowest set of locants
The lowest set of locants is defined as the set that, when compared term by term with other locant sets, each cited in order of increasing value, has the lowest term at the first point of difference; for example, the locant set ‘2,3,5,8’ is lower than ‘3,4,6,8’ and ‘2,4,5,7’.
  (…)

Especially note that the locants are cited in order of increasing value when they are compared.
Thus, the locant set ‘2,1,5,3’ is regarded as ‘1,2,3,5’, which is lower than ‘1,2,4,6’.
Therefore, the correct name is 2-bromo-1-chloro-5-fluoro-3-iodobenzene.

