This model demonstrates the effect of volume sensitive
seasonal unit costs on the cumulative gross margin of
the business. The unit cost are different for each month of the year and there is a discount if the volume is greater than 10. Therefore the per unit cost is set up as a table with two rows ( one for each price break) and twelve columns (one for each month). Be aware that the columns of a table are not connected to the steps in a model.
The variable "Total Cost" checks to see if the units are more or less than ten, and sets the local variable "price_break" to the appropriate row numberl. It then uses the MONTH() and TIME functions to determine which month of the year it is and sets the local variable "current_month" to the month number. It then uses these two local variables in the RC notation for the reference to the table element "Unit cost" to insert the correct unit price for the given month and unit volume.
