i think 250m is too much for ico.
You should read back the terms and co.
They didnt aim for 250m.
They have hidden cap. If that fund get over the hidden cap within the 1 hour perid. It gonna stop after 1 hour.
And they
have decided to allocate any proceeds collected in the minimum hour which exceed the hidden cap as follows:
20% will be allocated to the BNT Ether Reserve, to further improve the liquidity of BNT, which increases stability while reducing conversion costs (price slippage) for all.
80% will be locked for two years in a smart contract that will buy back BNT for 0.01 ETH (the initial price) whenever it is available, according to its calculated price. The purchased BNT will be added to the Foundations long-term budget, and after a 2-year period, any remaining ETH will be allocated pro-rata according to the Use of Proceeds chart in our Token Creation Terms.
https://blog.bancor.network