Why do we now need to claim our claim?
Nah, you don't "claim your claim".
You check the corrections we might have made to your balance.
An example of a case that needed a correction : if you've sent money out just before the site was taken down it didn't actually get sent but was deducted from your balance.
You should be able to get a refund based on a claim for the full amount, not the amount being deducted of a transaction that never happened.
So basically you check that we have made the corrections that we had to do and if you're ok with it you sign it off, there is no Ctrl+Z with Bitcoin, when money is sent it's sent. That's the reason we're going on the safe side.
was that in error or did I miss the window
Yes, it was an error. As explained you'll have 3 full months to sign your claim off. But if you do it during the next couple of days you'll get paid next Friday.
What does puzzle me though is the large gap between the claim window closing and the processing required in order to put the final "claim claim" into motion
The sign-off interface should be put online today, is it that big of a window ?
If someone reports a massive mistake on our side during the first seven days we'll have to recalculate everything, if not we're good.
If someone reports such a mistake afterwards we'll have less latitude to fix it so we'd really like it if we could send a massive transaction next Friday and forget about it.
surely in all the preceding days the bulk of this processing could have been done ready for the initial claim window closure.
Yes, the bulk was already handled.
BUT, I am making the assumption that they didn't get several million conflicting claims to sift through on or near the very last day - the reality is that the only people who know are davout & co. So I'll just shut up and be patient :-)
Guess what, I don't know, I don't have access to the claims DB directly. The work on the Instawallet claims is clearly split among multiple people to ensure proper oversight.