Yes, that's pretty much all it does and just how it works; like I said, it's just an unofficial hack. :^) We haven't developed any way to make it appear on every page as soon as the page is loaded; it only appears after the cart has been viewed on the page, and it only shows the cart total and how many items are in the cart, and that's as far we we've developed it.
Conceivably, adding custom javascript into your page might be able to adapt this further towards what you need; if you'd want some help programming that, we can recommend the competent, E-junkie-experienced developers listed in our directory here:
http://www.e-junkie.com/ej/developer-directory.htm