Performance Issue with flip down tiles

I'm working on a project that produces a display of flip down tiles that counts down to a specific date (for an event countdown) and I've pretty much got the animation nailed.

However, I'm finding it hard to get the performance up to a high enough framerate for it to work smoothly.  I'm fairly new to papervision3d and have tried some things (cacheAsBitmap for my movieclips, baking textures, setting moviematerial.animated to false where possible etc.) but now I'm really stumped!

I've attached my source code and a link to the working demo can be found here: http://sites.google.com/site/anatomicdesign/flip-tile to show the text, click outside the tiles and it should animate in.

Currently, the way that this works is to produce two sprite's with text boxes that can be updated (though actually I can't seem to get the textformat to update to show a different color!).  These are used as the material for four planes which are positioned to make a tile and are the DisplayTile class.  A row holds several DisplayTiles (default  34).  A message can be written onto a row (upto the character length) and one of the rows has been extended to produce the countdown effect.

I'm stumped as to how to improve the performance of this, so any help will be gratefully received!!

Many thanks,