Yes they are defaults. You should never have to change them. However, here is what they do:
1. Buffer and Packets determines the performance of the data transmission from the ECU to the computer.
2. Display Delay = Screen refresh interval.
3. Timeout = How long to wait to set the Map Trace to "Idle" status if no data is sent back from ECU. When the status is set to "Idle", it means that Map Trace is currently inactive, ie the ECU is not transmitting any data and Turbo-Tuner is not listening for any data.
The reason why they are adjustable settings is so that if someone does experience problems, then these settings can be adjusted to try and fix them.
But as mentioned above, you should not change them unless advised to do so by me.