hashrate calcs are not entirely accurate, and impossible to properly calculate when there's such a drastic increase followed by sudden decrease.
Stop avoiding the issue. You're not making any more money by mining this way, especially mining LTC for hours without paying out, you're not doing anybody any favors.
If you are a pool owner, you do your own hashrate calc based on the block numbers and timestamps, it's not very hard arithmetic, yet I see pool after pool screwing it up. Some people do stoopid things like take an average since the last diff change, or over the last 100 blocks, rather than say over the last 10min. which would be more relevant.
I don't do my own hashrate calculations, there is no reason to. For scrypt coins I use the getnetworkhashps function that's built into the client.
Even if that was off, for some reason, you can still see the dramatic difference between the last two difficulty dips and the previous ones.
Well, the best way it calculate is just to see how many blocks were mined by multipool:
From block 56250 to block 56500 (those are 250 lower difficulty blocks), there were 160 blocks mined by multipool, which means multipool had 160/250*100 = 64% of the network
The client said the network peaked at 871Mh. Most likely what happened is we switched faster and mined a bunch of blocks before the rest of the non-multipool hashrate came in.
Exciting times ahead with arguably the best services of any alt coins coming for arg and dgc!