The user manually adds SWS1 and SWS2 (slow wave sleep 1 and 2) sleep stage markers to their EEG waveform in the Signal Grid. They are likely using hotkeys to do this (NumPad 4 and 5 will add SWS1 and SWS2) the right-click menu (highlight section of data, right-click -> Sleep Stage).
Next, the customer will create a custom Marker Grid (Add Sheet -> Empty Marker Grid then Add Column -> Markers). In the Add New Marker Column dialog, they check "Show all available markers" and checkbox their desired sleep stages (including Sleep-SWS1 and SWS2). When the Marker Grid populates, periods of data that were marked using the SWS1 and SWS2 sleep stage markers will be blank instead of labeled by their stage label (1 and 2).
The user hasn't configured Neuroscore to use a sleep stage marker group that includes the SWS1 and SWS2 sleep stage markers. While they can use the hotkeys to add the SWS1 and SWS2 markers, they're not supposed to be available if the marker group doesn't "define" them.
The user needs to set the Marker Group used by Neuroscore to Rodent Sleep Ex or Large Animal Sleep to allow for SWS1 and SWS2 (and SWS3 for Large Animal Sleep) to appear on their custom Marker Grid. The Rodent Sleep (no Ex) only offers a generic Slow Wave Sleep marker (SWS).
This change can be made in Neuroscore by going to Tools -> Options. In the Options dialog, go to Workspace. Change the Marker Group drop down to Rodent Sleep Ex or Large Animal Sleep.