Hi
If that house get 330/50 then why should mine get it as well as all houses are are the same connected to cabinet 8? See screenshot below
The only way to know is order it and find out. No one here can possibly answer your question as to why or what speed you will get as we don't have the information. BT are the holders of more information than any of us, but yes they can have mistakes in that data, again you'll only know for sure when you have a working G.Fast connection. G.Fast frequencies can fall off a cliff over just a few metres, and we don't know how your telephone line route compares to next door or next door but one. Another 10 or 15 metres can easily see G.Fast drop from top speed to something less impressive.
There is likely to be more than one distribution point on your street, so somewhere along it you will get a split, where one house goes to one distribution point, and next door goes to another. Say that DP is further up the street away from the PCP, then the telephone line travels away from the PCP, joins the distribution point before travelling back to the PCP, easily adding many metres of distance.
It doesn't matter how many posts you make on the subject, or who you email, you will not get any confirmation of being able to get anything more than the Low estimates.
Either decide not to order G.Fast and let the subject drop, or order it and find out what you can achieve in reality.
Regards
Phil