I have a question. If I add up more sp delegation to you after 7 days, then what happen to curation rewards? Let me say, if I update my sp delegation to you from 40 to 60 on 8th days of my first delegation, then do I need to wait for another 7 days after that to get curation rewards of 60 sp? Or just another 7 days of updated volume of 20 sp?
Ah, I don't track every delegation separately so in your example, after delegating 60 SP, your share will increase and by this your curation rewards - so you will receive curation rewards like you've delegated 60 sp since day one. But, the actual curation rewards for @tipU will be increased after next 7 days (payout delay) and by this your's too.
For 40->60 sp that's not a big problem, but if someone would delegate 1 sp, wait 7 days and then delegate 100k sp - that would be a problem :)