The DAQ2/3 plugin works with the IIO Oscilloscope. You always use the latest version if possible. Changing any field will immediately write changes which have been made to the DAQ2/3 settings to the hardware, and then read it back to make sure the setting is valid. If you want to set something that the GUI changes to a different number, that either means that GUI is rounding (sorry), or the hardware (either the AD9144 (DAQ2), AD9152(DAQ3), AD9680 (DAQ2/3) or the FPGA fabric) does not support that mode/precision.
The DAQ2/3 view is divided in three sections: