Buffer issues

Hello, I'm testing the beta version and I don't really understand how the buffer works. I've been playing a lot with the prebuffer length and buffer length but it seems to change nothing at all. The progression status bar (in light grey) has always the same size even if I change the buffer settings.
The only way I found to really increase the buffer size (have a larger grey status bar) and avoid skips when driving is to setup my own icecast server and change the buffer in the server itself. But with that, I have another problem I'll try to explain you.

  1/ I set the burst size (buffer) of my icecast server to :
  <burst-size>393216</burst-size> (= 384 kb)
If the connection is lost during some seconds (which you can do with setting wifi off 5 seconds then on), everything works fine with the smart recovery ON : the stream continues

2/ I set the burst size to something bigger :
  <burst-size>524288</burst-size> (= 512 kb)
Now the light grey bar is larger and buffer is good enough for me.
BUT if the connection is lost during some seconds, when the datas come back, the smart recovery will load again the whole buffer size. This will result in hearing once again a part of a song I just heared before the data connection was lost.

 I don't know if it's clear enough as my english isn't perfect :)
To resume : how can I have a better buffer (= a bigger light grey bar)
and why when setting the server buffer size to something larger than 384 kb the smart recovery plays a part of a song 2 times when connection is back ?

If you want I can give you my server adresses to test
This was made on galaxy s3 with your last beta on a 48kbps aac+ stream
Thanks