Excel formula Help Needed SUMPRODUCT

Flora Sim , it's possible to avoid helper columns with formulas like this for the amount

=SUMPRODUCT(
   ($A$3:$A$20=$F3)*$C$3:$C$20*
   (OFFSET($B$3:$B$20,-1,0)-$B$3:$B$20)*
   ($B$3:$B$20<AGGREGATE(14,6,1/($A$3:$A$20=$F3)*$B$3:$B$20,1))*
   ($B$3:$B$20>AGGREGATE(15,6,1/($A$3:$A$20=$F3)*$B$3:$B$20,1))
)+
   ($H3-AGGREGATE(14,6,1/($A$3:$A$20=$F3)*$B$3:$B$20,1))*
      INDEX($C$3:$C$20,
         MATCH(1,INDEX(
            ($A$3:$A$20=$F3)*
            ($B$3:$B$20=AGGREGATE(14,6,1/($A$3:$A$20=$F3)*$B$3:$B$20,1)),
         0),
      0))+
   (AGGREGATE(15,6,1/($A$3:$A$20=$F3)*$B$3:$B$20,2)-$G3)*
      INDEX($C$3:$C$20,
         MATCH(1,INDEX(
            ($A$3:$A$20=$F3)*
            ($B$3:$B$20=AGGREGATE(15,6,1/($A$3:$A$20=$F3)*$B$3:$B$20,1) ),
         0),
   0))

See Sheet1, I added empty row after the headers of main table not to complicate formulas more. Perhaps it could be simplified, but in any case will be bit hard for the maintenance.

It's nothing wrong with helpers column, but only if they are help. In your case you generates it practically manually checking the names and dates and changing formula in helper column depends on their combination. I'd suggest to automate number of days column like

=IF(B2=AGGREGATE(14,6,1/($A$2:$A$19=$A2)*$B$2:$B$19,1),
   INDEX($I$3:$I$14,MATCH($A2,$G$3:$G$14,0)),
   $B1)-
 IF(B2=AGGREGATE(15,6,1/($A$2:$A$19=$A2)*$B$2:$B$19,1),
   INDEX($H$3:$H$14,MATCH($A2,$G$3:$G$14,0)),
   B2)

After that use summary formula for the amount as Geoff1951  suggested, the only I'd avoid array formulas their possible, thus

=SUMPRODUCT(($A$2:$A$19=$G3)*$C$2:$C$19*$D$2:$D$19)

See Sheet2 attached.