Share 'Mathmos Astro - Why So Little Wax?'

Just got my shipment of Mathmos bottles in (thanks a bunch Drew!). I looked them over and the clarity is unreal. I also have to ask - what's with the 90% water and 10% wax ratio? There is very little wax in these things. What am I missing? Compared to a USA 52oz, it's about half an inch less wax in the bottle. I am a little confused on that. Any info?