Hi Denis,
the LSD calculation is described here: http://help.sap.com/saphelp_ewm93/helpdata/en/f2/c7cb53ad377114e10000000a174cb4/content.htm?frameset=/en/e2/cecb53ad3771…
The rounding is an important factor, as usually it is simply not possible to calculate this time exactly (the system can calculate it, but it does not know all actual circumstances).
This overdue calculation is a strange thing, I have never worked with it. The time you enter there is the time WHEN something is overdue (so if you enter 2 hours, it shows you WTs which are overdue in 2 hours). But I do not really understand how this overdue time is calculated. And what you want to do (creation time + your 1 hour) is not possible in the selection there. But this you can actually enter in the "normal" list display of WTs (under "Documents --> Warehouse Tasks"). The selection screen has the creation date, you just create a variant with a dynamic date / time calculation.
In the Monitor you can get a display of overdue tasks, but you where looking for an active process by the system, then the measurement service would be the choice.
Brgds
Juergen