MPU9150 MotionFit Wireless SDK Data Output

We received 1 week ago the MPU9150 MotionFit Wireless SDK to be used for a new development. In order to better check the default data output we traced data using Realterm.
We see infact the expected packet with Quaternions sent at a rate of about 40 Hz (I thought it should be 50 Hz). We tried also to cycle between the 5 modes:
INV_NINE_AXIS -> INV_SIX_AXIS_GYRO_ACCEL -> INV_THREE_AXIS_GYRO -> INV_THREE_AXIS_ACCEL -> INV_THREE_AXIS_COMPASS -> ...
using the mfs command string sent via Realterm.
During this operation we observed that only the first 2 modes generate data, in the other 3 cases non data are generated. Data generation starts again when we cycle up to the first mode.
We also try to get Gyro data, when in INV_SIX_AXIS_GYRO_ACCEL mode, using mfg command string sent via Realtem, in this case we obtained 2 packets with Gyro value and drift every second, within the usual Quaternions packet still transmitted at about 40 Hz.

Please can someone explain why we see data only in the first 2 modes and how we can get Acceleration and Gyro data at the same time with a frequency of at least 40 Hz.

Thanks in advance for the help