Hi,
Sumproduct and Subtotal can get incredibly confusing. Try this:
=(SUMPRODUCT(SUBTOTAL(3,OFFSET(H$28,ROW($H$28:$H$5076)-ROW($H$28),,1)),--($A$28:$A$5076=A2),$H$28:$H$5076))+(SUMPRODUCT(SUBTOTAL(3,OFFSET(I$28,ROW($I$28:$I$5076)-ROW($I$28),,1)),--($A$28:$A$5076=A2),$I$28:$I$5076))
Thanks