SUMPRODUCT using 2 column headings as criteria

I have a data set with 2 column headings.

I can sum all the data where row 2 = 0
=SUMPRODUCT(('Weekly Hrs'!L4:S4=0)*'Weekly Hrs'!L8:S19)
and I can sum all the data where row 1 = Phase!A5
=SUMPRODUCT(('Weekly Hrs'!L5:S5=Phase!A5)*'Weekly Hrs'!L8:S19)

However, when I try and do both: ie: sum all data where row 2 = 0 and row 1 = Phase!A5
=SUMPRODUCT(('Weekly Hrs'!L5:S5=Phase!A5)*('Weekly Hrs'!L4:S4=0),'Weekly Hrs'!L8:S19)
I get a #VALUE error: a value used in the formula is of the wrong datatype.

Any suggestions on where I'm going wrong please?

Design	Test	Test
0	1	1	1
4	4	3	3
1	1	2	1
0	2	1	3

You changed the syntax from

=SUMPRODUCT(('Weekly Hrs'!L4:S4=0)*'Weekly Hrs'!L8:S19)
to
=SUMPRODUCT(('Weekly Hrs'!L5:S5=Phase!A5)*('Weekly Hrs'!L4:S4=0),'Weekly Hrs'!L8:S19)

Try
=SUMPRODUCT(('Weekly Hrs'!L5:S5=Phase!A5)*('Weekly Hrs'!L4:S4=0)*'Weekly Hrs'!L8:S19)

Thank you, Jonmo1 and ChemistB that's perfect!

You're welcome.

Actually, I now need to take this one step further:
I have a Rate column that I need to apply to the values before I sum them.
So if my rate column was:
4
5
6

I would have (4*4)+(1*5)+(6*0) as the result for Design and 0 criteria.
So for all Design cells that have 0 I need to multiply the value in the cell by the rate before summing. Is this even possible?
I've attached a spreadsheet example of the data which would hopefully clarify if I haven't explained fully.

example.xlsx

You can just multiply in the Rate column

=SUMPRODUCT(($B$5:$E$5=A1)*($B$4:$E$4=0)*$B$6:$E$8*$A$6:$A$8)

That's fantastic, you've saved me hours of poking at this.
Thank you very much!

You're welcome