We don’t know much about this, we’ve never done it.
However, if you click on the ‘VIP Gift’ button, it should show the EXP required for each level:
You can select the level you’re curious about, and it should tell you.
The EXP required for each level can go quite high, so it isn’t ‘100 ambers per level’ so far as I’m told. Otherwise it would have taken APOCALYPTICO about 5-20 seconds to get the VIP12 rewards, when he took a while and seemingly got the GoW after Luna. However, it might be 100 ambers per VIP EXP point, and you also get a small amount of that automatically over time. So the amount of days taken to receive VIP12 would be very high, if you weren’t recharging many ambers. However, getting there through other means is costly. Regardless, few people have probably reached VIP12 on DL, and even some of the top spenders lack the Goddess of Wisdom and assorted paraphernalia.