Question about report

Hi every one…!
I have to do a report abut how many hours spend time the pump on
night shift and day shift:
I have an hour totalizer tag :
day shift: 7 am -19 pm
hour on day shitf = tag(7am) -tag(19pm)

nigth shift 19pm - 7am = tag(7am) -tag(19pm last day)

Some one could help me?

I try this but the time is not equal