It is either 240 blocks or 12 hours for readjustment, not 48 hours. Or did I read your website wrong? LOL
It's ok, I can help you with the math. 240 blocks is only 12 hours when running at 3 minute blocks.
If hashing power is balanced at say 1 million diff and blocks are at 3 minutes and all of a sudden hashing power drops to 250K then to readjust it's going to take 4 times longer. ie 48 hours. Hope that helps. Good luck with your future trades.