mock exam关于IO的一道题：

Notes：even if the higer rate must be used to discount the improved cash flows, there is usually a range above the contract rate for which the price increases.

Mock 45题的解释：the net effect may be either a rise or  a fall in IO value.

是不是有点矛盾？不知道是不是我英文理解有误：我觉得notes 的意思是说if interest rate rise---net effect  is a rise.