A firm has two types of sales for one product: online and mail order. The firm understands these two types of sales to be substitutable. The firm's standard mix is 4 online sale(s) for every 9 mail order sale(s).

Online sales bring in $20 each

Mail-order sales bring $9 each

The firm's actual sales were 10,000 total units with 4,000 online sale(s) and 6,000 mail order sale(s).

What is the firm's mix variance for sales?

NOTE: only input a number, without indicating favorability (for simplicity, I've made sure that the relevant variance equation leads to a positive number). Round final answer to cents if necessary.