It looks like these are EXACTLY the same...Will my sequences from the PA 4X play in the PA1000? Also I had saved probably 75 -100 songbook songs I set up to a USB in the PA4x.

Will that load up?

I can hear the difference between the 2 boards, but if the sequencer is the same it would be huge if I go this way

The spec and feature set of the sequencer on each of the boards is identical. They both have a generous capacity of 200,000 events.

The PA4X probably has more "programs" (voices), including some with built-in articulations, which Korg calls DNC. So any song calling for one of those voices may need to be revoiced for the PA1000.

A true Korgie might know whether a chord sequence from the PA4X will load and play on the PA1000, but my guess would be that it does. What you're really giving up here is the sound engine, keybed, and pro form factor. As you are a songwriter, each offers nearly equal faculty. My $.02.