Headband of Vast Intelligence and Languages

When I first started playing PF I came across something saying you received an additional language per +2 bonus on a headband of vast intelligence chosen at the time of item creation. This is how I've seen it played in the games I am a part of and in a lot of actual play podcasts, but I cannot find a rule in either 3.5 or PF that states this is the case.

Is this just a really common house rule or am I missing an entry somewhere?

I can't find anything specific but I don't think it's and issue to run it that way as long as like the skill it's locked in at creation.

I am having a stupid tech issue at the moment, but the CRB faq on adding languages addresses the question of int based language bonuses as well, TLDR version: the OP is running it correctly.

Found it bolding mine

Intelligence: If my Intelligence modifier increases, can I select another bonus language?
Yes. For example, if your Int is 13 and you reach level 4 and apply your ability score increase to Int, this increases your Int bonus from +1 to +2, which grants you another bonus language.
Technically, Int-enhancing items such as a headband of vast intelligence should grant a specific language (in the same way they do for skill ranks).

Thank you so much! This is exactly what I was looking for.