What is the difference between Floor Price and Cut-Off Price for a Book Building Issue?

Company coming up with Book Building Public Issue decided a price band for the issue.  The price band usually contains an upper level and a lower level.Floor Price is the minimum price (lower level) at which bids can be made for an IPO.Investors can bid for the Book Build IPO at any price in the price band decided by the company.  In Book Build process retail investors have an addition option to choose "Cut-Off" price for bidding. Cut-off price means the investor is ready to pay whatever price is decided by the company at the end of the book building process. Retail investor has to pay the highest price while placing the bid at Cut-Off price. If company decides the final price lower then the highest price asked for IPO, the remaining amount is return to the retail investor.