Is the margin (sales, subtract the cost of goods sold) by the percent of sales (%), which may be compared with competitors, or against themselves. That is compared with that previously in the past.
The margin (Sales less cost of goods sold) by a percentage of sales (%), which may be compared to a race, or a race with itself, that is, compared to those achieved in the past.
Is the basic profit sales cost of goods sold (broken). The per cent of sales (%), which may be compared with its competitors, or compete with yourself, said is compared with that made in the past.