I found a definitive answer to your question:
PASC has a specified decoder and encoder compared to just the decoder, in MPEG 1 Audio Layer 1 the encoder is just an example. I think you will have to send a modified mp1 to @drdcc to see if anything breaks. Because of this cascaded decoding and encoding is supposed to degrade less than other formats,
PASC does also not use the optional CRC error correction, because the recorders already do that on a data level. But I don’t think anyone else does this.
Transcoding up to mp2 and/or back is supposed to be possible in better quality because the frames stay intact. To be honest, this contradicts the claim of being robust, we will have to test.