Alvin,

The new restrictions profile won't replace the old restrictions profile.   If you're looking to swap these payloads on the 2 devices, you'll need to make the following changes.

1.  create a new smart group that contains ONLY the 2 devices you wish to include.  You'll see the option to select users or specific devices in the new smart group creation screen.

2.  edit the existing smart group that has deployed the old restriction payload to these 2 devices.   Leave that smart group as is, except add the two devices as excluded devices and save the smart group.

3.  Add the new smart group containing ONLY the 2 devices to the new restrictions profile.