Salesman Commission should be calculated according to the age of the stock. Eg. A user should be able to set that 0-1 year old goods will be in 1% Commission Slab. 1-2 Year old stock should be in 2% Commission Slab and so on.
This increases the chances that salesman would be interested in clearing the old stock first. It would be very helpful for fashion related business as stock gets outdated every year.