jcole21

Increase or decrease in Sales - Sales is an Income statement item. On common size analysis - you divide sth on the income statement by itself. So it would provide an answer of 1…. no value here.
Every item on income statement is divided by Sales to common size it. (So you would not know what happened).
Financial leverage - is Debt/Equity or debt/assets - both of which are on the balance sheet. and that you would get by dividing by Total Assets. This will tell you if sth increased or decreased properly.
More or less efficient use of assets - again going by the fact that assets would be divided by itself - no value here.