I may be being extrememly pedantic in this, but I think there is a difference.
If a country or organisation has more than one "official language" they have equal status and so you can distinguish between the first, second, third, etc official languages. Laws would be written in both official languages.
For instance, within the EU there are several official languages, so you could refer to the third, fourth or fifth official language ( German, English, French ) and official texts have to agree in all the languages.
On the other hand, there could be one "official" language, and other languages of secondary status which are recognised.
For instance, an organisation in The Netherlands could have Dutch as its official language (in which all its formal texts would appear) while also using English.
Perhaps I'm trying to split hairs.