Very Suprised to see no one commenting on which document is the latest issue. ie the most recently issued of the two.
This situation exists with a number of documents relating to the A300. Not only in the AMM vs IPC relationship but also regarding Vendor vs MPD limits. From the planning/schedule creation point of view it can be a minefield.
In this particular instance I would sign off with the lower limit as this would be sure to get the back office staff investigating it and making the appropriate phone calls etc.....