1 Onset of sleep from time the lights were turned off; this is called  sleep onset latency  and normally is less than 20 minutes. ( 2 Note that determining sleep and awake is based solely on the EEG. Patients sometimes feel they were awake when the EEG shows they were sleeping.
The direct cost margin is calculated by taking the difference between the revenue generated by the sale of goods or services and the sum of all direct costs associated with the production of those goods, divided by the total revenue.
The calculation for gross profit margin is revenue minus direct costs divided by revenue. For instance, a manufacturing company sells a product for $10,000 after generating $6,000 in direct costs, which leaves a gross profit of $4,000.Divide 4,000 by 10,000 for a gross profit margin of 40 percent.rofit Margin for a Distributor Vs. a Manufacturer. Profit margins measure expenses against revenue. Hemera Technologies/AbleStock.com/Getty Images. Businesses calculate their profit margins for a defined period as the ratio of profit to revenue.