Very good. And now we know and can sleep soundly at night
The trick is to keep it that way.
I have a GW1000 that had an Absolute offset = 0. It didn't stay that way. It requires periodic adjustments, but it drifts the least of my barometers, maybe only 0.2 hPa or so.
I asked Dr. Burch about long term drift of barometers and his answer was a bit surprising. He said that contrary to what the printed specs might say, in his experience of calibrating and tracking several dozen barometers over long periods of time, is that barometers do not drift in a straight line.
They can also drift back.
He also said that if you compare two identical high-end barometers, one might drift a lot, yet the other one, hardly budges.
You never know unless you check.