Below is a sample, is this what you're looking for?
<TABLE style="PADDING-RIGHT: 2pt; PADDING-LEFT: 2pt; FONT-SIZE: 10pt; FONT-FAMILY: Arial,Arial; BACKGROUND-COLOR: #ffffff" cellSpacing=0 cellPadding=0 border=1><COLGROUP><COL style="FONT-WEIGHT: bold; WIDTH: 30px"><COL style="WIDTH: 64px"><COL style="WIDTH: 64px"><COL style="WIDTH: 81px"><COL style="WIDTH: 74px"></COLGROUP><TBODY><TR style="FONT-WEIGHT: bold; FONT-SIZE: 8pt; BACKGROUND-COLOR: #cacaca; TEXT-ALIGN: center"><TD> </TD><TD>A</TD><TD>B</TD><TD>C</TD><TD>D</TD></TR><TR style="HEIGHT: 17px"><TD style="FONT-SIZE: 8pt; BACKGROUND-COLOR: #cacaca; TEXT-ALIGN: center">1</TD><TD style="TEXT-ALIGN: right">11:00</TD><TD style="TEXT-ALIGN: right">19:30</TD><TD style="TEXT-ALIGN: right">8:30:00 AM</TD><TD style="TEXT-ALIGN: center">08:00</TD></TR><TR style="HEIGHT: 17px"><TD style="FONT-SIZE: 8pt; BACKGROUND-COLOR: #cacaca; TEXT-ALIGN: center">2</TD><TD style="TEXT-ALIGN: right">11:00</TD><TD style="TEXT-ALIGN: right">15:30</TD><TD style="TEXT-ALIGN: right">4:30:00 AM</TD><TD style="TEXT-ALIGN: center">04:30</TD></TR></TBODY></TABLE>
<TABLE style="FONT-SIZE: 10pt; BORDER-LEFT-COLOR: #00ff00; BORDER-BOTTOM-COLOR: #00ff00; COLOR: #000000; BORDER-TOP-STYLE: groove; BORDER-TOP-COLOR: #00ff00; FONT-FAMILY: Arial; BORDER-RIGHT-STYLE: groove; BORDER-LEFT-STYLE: groove; BACKGROUND-COLOR: #fffcf9; BORDER-RIGHT-COLOR: #00ff00; BORDER-BOTTOM-STYLE: groove"><TBODY><TR><TD>Spreadsheet Formulas</TD></TR><TR><TD><TABLE style="FONT-SIZE: 9pt; FONT-FAMILY: Arial" cellSpacing=0 cellPadding=2 border=1><TBODY><TR style="FONT-SIZE: 10pt; BACKGROUND-COLOR: #cacaca"><TD>Cell</TD><TD>Formula</TD></TR><TR><TD>C1</TD><TD>=MAX(A1:B1)-MIN(A1:B1)</TD></TR><TR><TD>D1</TD><TD>=IF(C1<=TIME(6,0,0),C1,C1-TIME(0,30,0))</TD></TR><TR><TD>C2</TD><TD>=MAX(A2:B2)-MIN(A2:B2)</TD></TR><TR><TD>D2</TD><TD>=IF(C2<=TIME(6,0,0),C2,C2-TIME(0,30,0))</TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>