[1000mp] FT1000MP tuned / flat settings

[Bruce]

    I have an odd finding with the use of my FT1000MP flat/tuned menu feature.  Curious to know if it is unusual, or an indicator of a fault somehwere.
    On 80 m, bottom of band in cw mode, using the IPO with menu 8.4 set for tuned; the receiver gain is higher while using the IPO.  By about an S unit.
    On the other bands, and higher on the 80 M band, the IPO use while menu 8.4 is set for tuned produces a lower gain, as I would expect.
    Any suggestions ?
brgds / Bruce