Extend is the #1 source of 'two songs glued together' syndrome. The new section drifts because Suno only loosely references what came before. You have to handcuff it to the original.
1. Copy the original Style box verbatim into the Extend. Don't paraphrase, don't 'improve' it. Identical style = identical sound. This alone fixes most jarring extends.
2. Bridge the seam with a bracket:
[Seamless continuation, same tempo, same instruments, same energy as previous section]
as the first line of your extend lyrics. Explicit continuity instruction.
3. Extend from a stable moment. Don't extend mid-chorus or mid-build — extend from the end of a verse or a calm outro moment. Clean launching pads make clean landings.
4. Keep the extend short. 30-60 seconds per extend, chained, beats one giant 2-minute extend. Short extends drift less.
5. If the seam still jars, generate 2-3 extends and keep the smoothest, or crossfade the joint in a DAW (5-second crossfade hides almost any seam).
Good luck! Hank founder of SonorixPG