when refreshing a Sandbox what is the time point of the new Sandbox configuration? Does the new SB have the Production config and data as at the time of clicking "Refresh Sandbox" or does it have the config from the latest backup point? or some other point?

“The new sandbox contains a copy of account data that is a snapshot taken from your chosen source account at the time of the sandbox refresh request” At least according to the warning box on the docs.

Sandbox refresh grabs production data from the most recent nightly backup, not from the exact moment you click "refresh." So if you refresh on Wednesday morning, you're getting Tuesday night's backup data. The refresh doesn't create a real-time snapshot of production at that instant. Configuration and customizations come over with that backup point too, so you're getting everything as it existed at backup time. This is why NetSuite recommends doing refreshes during off-hours when possible. x

The sandbox refresh went ahead including the most recent changes within the same day.