Using latest SL 2015 WebApps build 092818MD, I am finding there are 3 "WA" Control Parameter flags that do not seem to have an impact on the Timecard display:
DIS-TIMECARD-GRID-DESC (I believe this should control the ability to display the Description field in the TimeCard grid)
DIS-TIMECARD-GRID-DI-BTN (I believe this should control the ability to display the Day Info/OT button on the TimeCard)
DIS-TIMECARD-GRID-IC-BTN (I believe this should control the ability to display the Invoice Comments button on the TimeCard)
Looking at the available source code, I am not able to determine how this should work, or if code changes are required to allow the functions to work correctly. I also don't see the above control parameters in any of the documentation (Release Notes, Deployment or User Guide) that comes with the code.