x-post from Slack
The block height was selected based on a date and time requested by Cryptopia - I used the requested date and calculated which block height that would fall on.
Spreadcoin has 1 minute blocks, so I worked out how many minutes between a recently issued block and the 10th October at 10am New Zealand time.
The release of blocks is subject to variances. Spreadcoin will release blocks 'approximately' every 1 minute. Over a long period of time, it averages 1 minute, but if have ever watched a block explorer, you'll see that some blocks are produced within seconds of each other and other times blocks are several minutes apart.
Ok, why am I explaining this?
Do not use the 10th October, 10am New Zealand time as the cut off date and time. That is just something you can use to give you an approximation.
The block height 1657200 is the snapshot cut off time and only the 1657200 block height.
If you have never used a block explorer, you might want to take a look now so you can figure out how to use it as a count down timer. You'll only need to do this if you plan on leaving the final location of your Spreadcoins to the very last minute (please don't).
https://chainz.cryptoid.info/spr/or
http://cryptoguru.tk/CurrencyList/index.php?Currency=SPRNB: The Spreadcoin wallet is the best place to keep track of blocks.
As Bitcoin difficulty has increased, the official release times for each block is 10 minutes, but it has reduced down to closer to 9 or 8 minutes.