First of all, make sure you have Smart Recording disabled. You need to record every second for the PT data to be accurate.
If you have Zero Averaging turned on, that means all the moments you are producing zero watts will be included in the average (WKO also calculates AP in this way, so the two figures should be the same). So if you want to see the same AP in the display as you'll see later in WKO, then turn Zero Averaging on.
If you turn Zero Averaging off, the 705 display will show the average power exclusive of any stops, coasting, etc. This is probably what you currently have, hence the different figures in WKO. What I've found is that this figure ends up being a good guesstimate of my normative power, but whether that's true for anyone else depends on their riding style. These days I keep Zero Averaging on and calculate my NP on the fly in my head by estimating my VI.
Note that whether Zero Averaging is off or on, it's only the real-time display that's affected. The 705 records the same data either way as long as you have Every Second recording turned on.