I know there is confusion on this forum and you should really try to ignore it. I don't really understand why this persists. However, the guidance does not help in some ways as it refers in the most part to simultaneous applications of the main applicant and dependant (paras 42,44 & 45). However, it does specifically go on to cite the requirements when a dependant is applying separately in 43 and 46.
46. If a family member applies separately from the Tier 1 Migrant, there must still be enough funds to support each member of the family. Therefore in the example above, if the family has a third child, the main applicant has been in the United Kingdom for two years and the family applies for leave to remain for the third child separately, they must provide evidence that they have an additional £533 in available funds
So, in your case, if you have not been in the UK for more than 12 months it will be 1600 x 2 held for 3 months.
Also see.
Annex E of the immigration rules