Row\Col
A
B
C
D
2
kWhr
Cost
Delta
3
0.0
$0.15
$0.15
 C3: =B3-N(B2)
4
12.0
$0.19
$0.04
5
15.6
$0.28
$0.09
6
24.0
$0.32
$0.04
7
8
kWhr
Total
9
10
$1.50
 B9: =SUMPRODUCT((A9>$A$3:$A$6) * (A9-$A$3:$A$6) * $C$3:$C$6)
10
15
$2.37
11
20
$3.72
12
25
$5.16
13
30
$6.76
14
35
$8.36
15
40
$9.96
16
45
$11.56
17
50
$13.16
18
55
$14.76
19
60
$16.36
20
65
$17.96
21
70
$19.56
22
75
$21.16