"Gain" in Cocosdenshion with value more than 1.0 won't take any effect on iOS?

Is this normal? If this is so, then I have to export sound file with level of volume at max in use then lower down with gain value in code (but not higher value than 1.0).

You can see http://stackoverflow.com/a/7896375/571227 and http://cocos2d-iphone.org/wiki/doku.php/cocosdenshion%3Afaq. The latter try to look for “What values can I use for gain?”.