Text Box for selected words

Hi everybody;
I'm trying to create a dynamic link template and I stuck on this problem. Basically I need to create text boxes for selected words.

I'm using sourceRectAtTime expression plus range selector (word mode) to create text box for selected word. Text layers will be single line and left aligned.All I need to do is, finding right expression for the position line.
For example; if I want to highlight first word, it works well; as you can see, I've added scale animator and got rid of normal text. Only highlighted text stays, so text box gets scale from this layer.

But if I select second word from range selector, it gets the scale of second word but I need to add correct expression to position to fit textbox to the second word.
Ps.Sorry for my poor English, thanks in advance.