When you do that, a completely different set of codes gets used when you are in dual-display mode. Click the button next to the checkbox to toggle between the two sets of codes:
You're probably missing the hidden count in the dual-display set.
For what it's worth, there's also an error in the codes you quoted. There should be a {h!} before the {rpad} on the first line. Without that, to match the other {h!} earlier on the line, the ({hi} hidden items) part is always displayed, even when there are 0 hidden items.
(The {h!} codes always come in pairs, surrounding whatever you want to hide when all the other codes in the surrounded section are zero/empty.)
(On the other hand, if you want "0 hidden items" to be shown then remove the first {h!} as well.)
Grab my codes from the Status Bar Codes thread.