Okay -- here's the skinny about WHY someone w/Vue 7 gets a cheaper upgrade. if you are already on Vue 8 (whatever version) - they've gotten money from you and gotten you on board w/their latest releases fairly recently.  If you're still clinging to Vue 6 or 7 its been a while since they have gotten either your cash or your buy in on their latest platform - if they dont get you on board you coupd go out and find some other solution for your scenery creation - hence the BIGGER enticement to upgrade.  Its really that simple.  And remember, for e-on, you only have an upgrade range of 2 versions before you are no longer eligible to upgrade at all.

I was out of the product cycle myself since Vue 4! up until this year.  E-on did a "hey you used to be one of our people" intro sales at the begining of the year that got me back on board w/some serious discounts. (to the tune of Vue 8 complete at this point).

From what I understand about the maintenance approach, they want a tight and guaranteed user base and a tight financial estimate to anchor the devlopment cycle of their product. That's why it exists to begin with.