Text style expression is not working with Essential Graphics

I am using Essential Graphics with Text layer and text properties exposed. Exposed properties is text size. In Source Text I have expression

style = text.sourceText.getStyleAt(0, time);
currentFontSize = style.fontSize;
style.setLeading(currentFontSize*2);

This expression works when properties are changed in Essential Graphics window. But when same Comp is imported in another composition, this link between FontSize and Leading is broken.