Hi,
I suggest to refer to a Business Content example: 0FI_GL_10. Here you can observe the following:
In this example only the lower limit is used. It means that the lower time stamp of the extraction will be based on the highest time stamp of the previous extraction minus the safety margin (i.e. 3,600 sec. = 60 mins).
Please try it out in your case. Feel free to increase the safety margin if you experience problems with missing documents (but I expect that 60 mins will do under normal circumstances).
Be aware that the DSO has to be designed for overwriting documents since some of them will be extracted and loaded twice. Also the transformation of key figures has to be set to overwrite.
Best regards,
Sander