In our example, ceiling sales (15000 satoshi) and base purchase (12000 satoshi) prices are different. This difference is for meeting all the token amount that can be circulated. I suggest you review the system.
There is nothing to review.This "system" is just a fantasy.No ICO project owner will offer 100% refund.
A better idea is to create a "middle-man" crowdfunding platform that will gather all token purshases and redistribute the coins to various projects,based on their level of popularity,trust,reputation,team and number of supporters.Such platform might offer a refund system or the ability to guarantee the token purchases.