a. Products can have case pricing i.e. UOM style - e.g. Buy individual for $9.99 each. But buy a case of 8 for $72 (avg price $9.00)
b. Products can have tier pricing i.e. Buy upto 12 for $9.99 each. More than 12-24 for $9 each. And above 24 for $8 each.
c. It is a combination of both, where we have single qty, plus case quantity plus tier pricing also. So you can buy single at $9.99, buy upto 12 for $9.99. Above 12 for $9.00. And a case of 24 for $200.
Please check this for better understanding : http://screencast.com/t/psNutkpkk4
Well you can manage bulk qty by tier price but it seems you've certain dynamic conditions like 8,12,24. (If i do not understood wrong)
As in current case you can also manage through tier price but for that you need to add all rows for all your conditions. My suggestion either do customization Or use tier price import module.
Hope it helps you