Hi rotibakar, nice post with clear instructions. Something i noticed too. When did you last try using the EOS distribution app? because it was update recently to use the 'claim' function instead of 'claim all' see my post here https://steemit.com/eos/@johnchamberlain/eos-token-distribution-instructions-update
I think the token claim is only to transfer to another wallet, the important part is registering before June 2018.
It's been about a week, I have not tried the most recent update to the EOS Distribution App so this guide might be a little backdated and obsolete by now...
In order to actually claim your tokens you need to register your key, doesn't matter when... But claiming your token will allow you participate in token trading in the market, which some people may be interested in doing. Really depends on what your intention is..