priority setting

[Formatting]

Is there a way to select a certain set of goods for processing depending on
which priority they are being set?
For example, in cells C10 to H10 I have the months from January to June
in cells B11 to B14, I have 4 sets of different colored screws, let say
"Blue" in B11, "Red" in B12, "Green" in B13 and "Orange" in B14
For January, I have 10 Blue, 11 Red, 13 Green and 17 Orange; so I enter 10
in cell C11, 11 in cell C12, 13 in cell C13, and 17 in cell C14
For the next month, I have the previous number of Blue + 4, Red + 3, Green +
2, and Orange + 1, as shown in the table below:

A B C D E F G
9
10 Jan Feb Mar Apr May
11 1 Blue 10 14 18 22 26
12 2 Red 11 14 17 20 23
13 3 Green 13 15 17 19 21
14 4 Orange 17 18 19 20 21
15
16 Left Over
17 Blue X X X X X
18 Red X X X X X
19 Green X X X X X
20 Orange X X X X X

Each month, I can use up to 50 screws. At the end of each month, I want to
know how many of which color are left depending on the priority I assign for
the colors.
For example, under case 1, I assign priority 1 (first to be used) to Blue,
then Red, then Green then Orange. The order of priority is given in cells A
11 to A 14.
Now, for case 2, what if I change the order and assign 1 to Blue, 2 to
Green, 3 to Orange and then 4 to Red.
How do I set this up so that I can automatically (for any combination of
priorities I assign to the color) get the number of Left Over for each color
represented as X in cell C17 to cell H20?