One of the main causes of incorrect readings when doing DC measurements, is that not all boxes wait properly for the output to settle when requesting a certain output level, or enabling the output. If you use the combination of a DC source and a DC meter to perform a force-sense calibration / sweep, integrated in the same box or using 2 different instruments, then you need to make sure that you allow the output of the source to settle, before doing the DC measurement.
To specify a settling time during DC calibration, first go to [Tools] - [Options...] in the menu of ICE. Under the Calibration section, you will find a check box "Automatically determine DC settling time". Make sure that this is unchecked. When launching the DC calibration then, in the page where you can define the calibration kits to use, a text box will appear allowing to override the default DC settling time.
To specify the DC settling time to use in one of the applications (e.g. ICEBreaker), you will typically find a setting for this where you can edit the sweep plan.
If you want to be sure, first test with a high settling time (e.g. 2s), and then gradually decrease this until you feel confident that you chose it well.