Business & farm

What about an invoice that has

furnace:  3000

thermostat: 10

Thermostat discount: -100

Base Cabinet: 400

install discount:  -400

install discount: -100

 

Can I apply those discounts directly to the furnace so that I can expense the furnace?

So I can expense 

furnace: 2500

thermostat: 100

base cabinet:400