1.5. Once the signal is locked, the "dot" in the display appears to jump up and down. Why?

This might be related to the configuration of the autolock. To test that, please try the following

1. In the Function list select "Settings"
2. Select the "Visibility" tab
3. Activate "Autolock" within "Advanced Functions"
4. In the Function List select "Lock"
5. Click on the "Autolock" tab
6. In the lower half click the "Advanced" tab
7. Make sure that the settings for "Cursor snap to set point" is NOT activated and that the "Smart Assistance" feature "Setpoint" is activated

More information about these features can be found in section 8.2.1.3 of the user manual.