The sustaining cost could not only caliculate from prim numbers but Avatars on the region, assets usages, etc. So that CTP is not suit for measure.

But yes! Linden Lab should have been made some rule on "Abusing use of OpenSpace" at the first place. Without making clear guideline or SLA, how could they able to say "We want to raise your tier." :/

I hope LL reconsidering this matter and maybe this time, only introduce some restrict rules about Abuse.