Session sample rate and clock

I have an Apogee AD16XHD, one DA16X and one 192 I/O, all clocked via an Apogee BigBen. When I load a session in ProTools (still on 8.1 on Macpro) shouldn't the interfaces change their clock accordingly ? It looks like I always have to manually change the bigben clock to adapt to the session sample rate. :o