Applescript (Adobe Illustrator) find coincident X coordinate on a path for any given Y coordinate

I have two lines as shown in the screenshot below (Adobe Illustrator file) which my script produces. Is there any way, using AppleScript, to find the value of X for the coincident points on the curvy vertical lines for any given value of Y? For example if I wanted to add horizontal lines between the two vertical paths at the points indicated on the screenshot... EDIT: I'm guessing that this is not going to be a built in function of AppleScript / Illustrator but I'm also guessing there must be a way to map a point on the path from the information used to build the path... ie the previous and next anchor points and the positions of the handles... Could anyone explain how this works? What the formula might be?