I have 2 f75's 1 is about 1 1/2 years old and the other I just got. In the manual on the first f75 they says in the DE mode below 5 & above 19 is high gain & 5- 19 is low gain. On the new f75 the manual says the sen. has two stages 1-29 is low gain, 30-99 high gain . Are bough of the manuals right .???? I know that the JE mode is a high gain.