If you are getting swirls come back, then that means the IPA did it's job 100% and removed the lubes (not fillers) and now shows true results.. Now that means you need to go back and repolish the section and maybe change to a more aggresive pad to cut out the defects and keep inspecting till the defects are gone.
Now if the defects are gone, you will see fine circular pad abrasions left behind from the pad and this is normal. It's now time for your finish polish.:spot
This is what true polishing is. Nothing more, nothing less!
What IPA is removing is actually the lubes. Some people call them fillers, but to be totally 100% honest they are just lubes doing their job.
Without the proper lubes, the abrasives would just dry up and char the paint while giving an uneven thickness of paint. Now with the abrasives emulsified in the lubes, it now runs cooler, longer, evenly, letting the abrasives "tumble" the scratches and swirls removing them while giving a great base gloss.
Now to answer the two questions... Does 203 fill and why are the defects coming back after I use IPA?
My logical answer:
"The power is in your hands and you are the machine. The buffer, polishes, and pads are only your tools... It's all how the machine fine tunes the tools to be the work of art"!
Good Luck!
Ryan Blanchette