Yes, another data point: my wife slipped to bronze because I'd booked us a trip for my January birthday convinced that her renewal date was February 8th. But it wasn't - schoolboy error as it's January 8th. Called and got the points from 11 & 14 January counted for the previous year. Silver retained - although it took two phone calls as the first agent didn't actually act as they said they would.
All to the good, and family holiday to Portugal went well with lounge access at both ends for four people (and we all really liked the QF lounge in T3 which we had almost to ourselves before the afternoon flight to LIS).
Moral of the story - the extension does work!