The SD diagram in your earlier post is the standard way of doing parallel/series switching. With the push pull 'up' the pups are linked in series and the neck volume works as a master, with the bridge volume having no effect.
The following layout is a little different. When in series mode the neck volume still works as the master but the bridge volume allows you to fade/bypass some/all of the bridge pickup giving you a bit more control over the series sound. The idea is to make it still loud but a little less boomy, and allow you to mix in some of the bridge treble without going full on. Essentially the bridge volume will control how much signal goes through the bridge pickup and how much bypasses it.
The 220K resistor is added in the series mode to reduce the pot's resistance across the pickup and flatten the taper of the pot. This makes the bypass/fade control a bit more progressive and less 'all or nothing'. I did some tests during the week with a 250K pot both with and without the resistor, and I definitely preferred it with. But, if you want you can just omit it from the layout and it will still work. (Note: the resistor image used in the diagram has 150K bands, but 220KΩ is correct value to use)
Just another option if you want something different.