Playback overview bar?

No that shouldn’t be the case. If I have a repeat starting at bar 1 and then a “close” repeat in bar 20 then the bar after that should be bar 21. Remember, this is a Notation program first. The Play window will reflect the notation i.e. bar 21 will be the bar after the “close” repeat. If you want to see 40 bars then you’ll have to duplicate the material instead of using the repeat barlines.