I would change your trigger from:
AND SubTotal of Items > 0
AND SubTotal of Items >= 120
Then add another shipping charge with:
AND SubTotal of Items < 120
With a flat rate charge of $40
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.