start time / end time are the prime time settings.
if you want to see all programmes on the day then they should be 00:00 and 23:59. Its the hour of the day

I didnt get the second part of the question well perhaps, but if you mean get the data for all selected channels rather than the currently selected one, then the answer is no, this has been done intentionally so we dont read too many huge xml files at once and make the application slow,