My CIV is a lowly 36 despite having just made gold again within 9 months.
I think a lot has to do with the type of tickets you purchase as opposed to the class you fly. I'm partial to tactical sale fares in Club so invariably I'm booked in I class. Or sometimes in Europe I might take a pro active upgrade offer to Club if I need the tier points but ultimately I'm still paying a fraction of what some tickets are costing. I'm imagining if I book flexible C or J class tickets then my score might increase but I don't want to do this. Also if like me a fair chunk of your gold comes from flying OW partners then I'm also guessing that this will have no bearing to BA on how they individually "value" or score you in this rating. My thought process is it just sorts the wheat from the chaff in identifying who out of all the status card holders who might be on board are the most commercially important to the airline in terms of revenue spend.