In terms of the axis, see attached taken from the manual, do the axis change if the sensor position changes, ie: if the sensor is rotated 45 degrees does the vertical axix X rotate 45 degrees or does it remain vertical?
If you are describing rotating the case 45 degrees, while remaining flat on the table, you would see a rotation indicated by the gyroscope on the Z axis while in motion -- this would be a rotation around the Z axis. The gravity vector would still be visible in the accelerometer as -Z.
If you rotate the sensor so that it is no longer flat on the table, you will see the gravity vector shift to indicate the new orientation once settled. The gyroscope would show the rotation during the movement.