May I ask why you're doing this?
There's a math puzzle factor to this and maybe a flip a coin aspect too. But over the last 3-4 months difficulty changes have been sort of unpredictable - there was even a decrease if I remember correctly.
All due to a looong list of factors that affect the total network hashrate, including the less obvious ones like homemade rig uptime lapses, to FPGAs being sent back to BFL, people going on holidays and just not caring, to individual miners switching to other pools, to solo, to other cryptocurrencies ....
Don't get me wrong I'm tracking things too but why such a real time approach?
No reason really. Just curious to see how its progressing.
Keep up the good work, I have several orders for ASIC equipment all expected to ship around Aug/Sep and if the diff is way too high then I will pull out as I don;t want a ROI to be longer than 3 months for what Ive paid as this data will give me an idea of were the Diff will be heading...