Classic B747 Cabin Altitude Question

[SRB]

Would any Classic pilots or FEs tell me what the cabin alitude settles at at normal cruising altitudes, and also at its higher cruising levels, please?

I've heard stories that it can "drift" up to 9 - 10,000 ft, but find this hard to believe. My machine's hooters go off at a cabin alt of 9,000 ft, which I thought was iaw the regulations.

Thanks.