If you run the formula on this data set ("Name" is in A3 and "Hours" is in B3) and the data is in A4:B20. What do you get when you filter for Bob?
=SUBTOTAL(9,B4:B20)+(SUMPRODUCT(SUBTOTAL(3,OFFSET(B4:B20,ROW(B4:B20)-MIN(ROW(B4:B20)),,1)),--(B4:B20>9),B4:B20))*0.5
[TABLE="width: 128"]
<colgroup><col width="64" span="2" style="width:48pt"> </colgroup><tbody>[TR]
[TD="class: xl64, width: 64"]Total Hours[/TD]
[TD="class: xl63, width: 64, align: right"]95.5[/TD]
[/TR]
[TR]
[TD="class: xl64, width: 64"][/TD]
[TD="class: xl64, width: 64"][/TD]
[/TR]
[TR]
[TD="class: xl64, width: 64"]Name[/TD]
[TD="class: xl64, width: 64"]Hours[/TD]
[/TR]
[TR]
[TD="class: xl64, width: 64"]Bob[/TD]
[TD="class: xl65, width: 64"]10.5[/TD]
[/TR]
[TR]
[TD="class: xl64, width: 64"]Bob[/TD]
[TD="class: xl65, width: 64"]15[/TD]
[/TR]
[TR]
[TD="class: xl64, width: 64"]Bob[/TD]
[TD="class: xl65, width: 64"]21.5[/TD]
[/TR]
[TR]
[TD="class: xl64, width: 64"]Bob[/TD]
[TD="class: xl65, width: 64"]12[/TD]
[/TR]
[TR]
[TD="class: xl64, width: 64"]Bob[/TD]
[TD="class: xl65, width: 64"]7[/TD]
[/TR]
</tbody>[/TABLE]