What does % vs. 52w High mean?
The Price vs. 52 Week High indicator compares the current price to the highest price at which the stock has traded at in the last 52 weeks (12 months), ie. the formula is : Current Price - 52 week High / 52 Week High.
To screen for companies that are within 10% of their 52wk high, the criteria would be Price vs. 52 Week High > -10 (i.e. greater / less negative than -10%). Here's a sample screen that you can fork.
Alternatively, if you wanted to set an alert for when a stock has fallen more than 20% below its high, you would set it for Price vs. 52 Week High < -20. Although the targeted value is numerically greater than 20, because it's a negative number, it needs to be shown as "less than".