Formula Too Long Problem

Hello fellow members. I am having a problem with a formula too long issue that I am hoping you
can help me with. I have a table of parts and within that table there can be 10 different models
and it can be sold in 20 different markets.

This table structure is used extensively throughout the workbook, so I am hoping I don't have to
change it in order to accomplish what I need to, which is to sum the total # of parts sold by month
for each model & each market the part is sold. Not every model may use the part and so the
user would just enter a zero for the quantity in the table under that model.

The part cost may be higher or lower than the base cost in each of the 20 markets sold and so the
user can enter a % increase/decrease for each of the 20 markets. However, not every market will
sell the part & so my thought was to have the user enter a 0% in the market increase % to indicate
this.

The problem is that when I multiply the quantity used by each of the ten models for each of the
20 markets (if the % of the market is zero) I get the error the formula is too long. I have tried to
come up with a different methodolgy, but so far have not been able to come up with anything &
still accomplish what I need to without changing the base structure of the table.

I have attached an Excel workbook as an example. The formula that is highlighted in the Parts
Sold Table shows the formula for just two models and two markets. If this formula is expanded to
include the ten models & 20 markets I need Excel indicates it's too long.

I look forward to any assistance you can provide me.