sumifs unique number vs multiple listing

[jw01]

hi all

i have in the "invoice" sheet, column AF, that has multiple invoice #s listed.

i need to sum from the "data" sheet column T, but for only a single "invoice" # in the invoice sheet, column BP.

I have attached a sample. I dont know how to make the formula only total for a unique invoice #, so it does not duplicate the values over and over , as invoices #s repeat.

can someone pls assist? thxs