logic 9 aggregate device, sample rate

Sorry to ask in this forum, but I thought someone might know how to help:
I have an aggregate device setup in Audio Midi Setup, a mackie firewire mixer (slave)which has a max 96k sample rate, and an apogee ensemble (master), 192k. I set the sample rate of logic to 192, and the inputs on the aggregate device/both interfaces record audio fine. The only question is, since 96k is the mackie’s highest sample rate, how is this working? I just don’t want to run into sample rate issues in the future, so I want to be clear. Can anyone help?