Thank you!
I sprayed the bumper with TS-63 Nato black while painting some other body parts with TS-29 semi gloss black. Turns out bringing out two cans of different blacks is a bad idea. This is a picture of the bumper accidentally painted black on the third coat.
After a few extra coats of Nato black, this is the result. In certain lighting conditions it looks green, and it's a bit too dark.
Currently respraying with TS-82 Rubber black, and it's looking much better. Left is TS-63, right is TS-82. It's very hard to tell them apart in real life without a direct comparison like this, but the TS-82 has a slight hint of blue and looks like slightly faded matte black plastic.