The second variable is not seen in the number of accounts. Only the ADS is reduced, the number of accounts stays at 10,000. If people create multiple accounts to get more free storage, the space allocated for free number must by necessity rise, not fall as in this example.
I think the ‘ADS for free’ system is inherently flawed. It’s a matter of time until easy ways to set up and manage multiple accounts have become widespread. I think the system should be designed in such a way that no multiple account exploits exist. Systems like ‘what you give is what you get’ or unlimited storage for free but extra costs for redundancy and better download speeds as I proposed a short while ago don’t have multiple account exploits:
https://maidsafe.org/t/safecoin-payment-for-extra-redundancy-download-speeds/400