Adding and subtracting set values depending on multiple criteria

[Rekragisao]

Dear Excel enthusiasts,

Today i come to you for aid in the construction of an excel form i'm making for my work to check if the usage in liquor bottles matches the sales reports.

As you can see in the example file attached each bottle has 5 categories of which all of them could be present at a set time. Each category also has a weight set to it in a different sheet.

What i'm looking for is a formula or custom function that does the following:

1. Find the same item in the sheet that has the weight values in it.
2. recognize the categories that have a value in them.
3. sum the weights appointed to the same categories in the weight sheet.
4. subtract the weight of the "empty bottles" from this weight

Any help to get me going would be much appreciated. I've been trying to wrap my head around it all day long but writing a decent function is above me and with a normal formula i keep getting errors.

With kind regards,

Rekragisao

[JohnTopley]

In L6

=INDEX($B$6:$F$6,MATCH(L$3,$B$3:$F$3,0))-INDEX($G$6:$K$6,MATCH(L$3,$B$3:$F$3,0))

Copy across

Format cells as CUSTOM 0;;;@ to "hide" zeros