In your link, the only evidence provided for such activity is a 2010 ChilOut report where it said they were given 6 at a time.
The parliamentary submission quoted the same 2010 report (ie. 6 at a time).
The only other reference is refugee advocate Victoria Martin-Iverson, who said: "Sanitary pads are doled out one at a time". What evidence did she have here?
It seems pretty unsubstantiated to me.
ETA: Why doesn't the link to Bowen's response work? I would like to read what he had to say.