Animated Texture Packs at 20fps

Jeb's notes on animated textures say they work at 10fps, I am not seeing this.

I was making a fairly large animated texture (the .png was 77Mb). I placed the frames from a movie at 0.1 second intervals, however the movie played through twice as fast. I had to generate the texture at 20fps to get normal playback.

I would also like to note that adding *2 to the .txt file didn't help for the large file, although I did get it to work when I put only two frames in the .txt file. (a further note, when using only two frames I also saw that the texture frame rate was 20fps)

Example:

Here is the bedrock.png I used, its quite big.
http://www.mediafire.com/view/?c5abgp7wuuput37
and the final texture pack,
http://www.mediafire.com/?1e2rpwt6hggy942

The bedrock.png has ~4600 frames. The image goes through ~231 seconds (213 seconds of images and 20 seconds of black at the beginning) of footage, or 20 fps