Prores file discrepancy

[chameleonate]

Hi there, wondering if someone can lend some expertise on a Prores filesize mismatch between two different systems and editors? I've been at this all day and am drawing blanks at every turn.

I am running Windows 10, Premiere Pro 2019 and have received Prores 422 HQ files from an editor. These all look great. I'm replacing the audio takes and rendering out also at Prores 422 HQ but getting file sizes that are half the original. We've exchanged notes and both have identical settings but his 1.31 GB files  render out this end at 644 MB. In one way this might be ideal to have massively reduced file sizes (the quality looks OK to my eye) but I am wondering how much precious data will be lost for when we'rte ready to colour and grade?

The footage was recorded on an Atmos ninja. For reasons no one has been able to explain, the DP set an incorrect frame rate for the entire shoot. These Prores files were then re-encoded by a friend down to 24fps. I am wondering if just the fact I am replacing audio would impact this, but can't see how.

Any ideas would be gratefully received,

Iggy

[chameleonate]

I've compared both files in GSpot and can see that  the original file is 179270 kbps, whereas my render is 85700 kbps. This has me a bit flummoxed as I can't see anywhere to alter the bitrate in Prores and have read it's not possible.

I'd appreciate any ideas. Cheers!