I’ve got it figured!
There was nothing wrong with my workflow (I knew it!!).
The sound was recorded on a Deva 5 using version 2.07.
The Deva can record 48048 but stamp at 48000 if using the F (for Fostex) facility. If FCP reads the stamp at 48000 it will automatically pull the sound down by 0.1% to match the picture that is running at 23.98. It is really important that this happens otherwise we will be really stuck when we get to the mix when we master back to 24fps.
So here’s what happened… Deva released a new version of their software – 2.10. That fixed it. The problem was with the Deva. No wonder older versions worked fine, it was just 2.07 that was bugged. FCP works like a charm now so no need to use the dodgy way that BWF2XML makes referencing pulled down files anymore.
Unfortunately, the Deva guys at Zaxcom don’t seem to be very aware of this problem and it seems to have been fixed by accident in the new version. They just seem to be going on about the Timecode Stamp Pullup and Pulldown buttons that don’t affect what I’m talking about at all.
If anybody else seems to be having this trouble, make sure that the Deva OS is 2.10!