Though I haven't done the calc run, I can confirm that there is AS YET no PAC for the 20m dipole/inv V.
I will have a look when I wake up properly.... nodded off watching a film till my phone went bing !
Two initial thoughts come to mind...
1. I am pretty sure that a PAC will appear in due time for a whole variety of "typical" aerial set ups. JAV and Co really are working hard on their modelling activities and PACs seem to be a priority with them as I read between the lines. I think they went for the low bands initially as a proof of concept to Ofcom in an area where, as some would see it, Ofcom are struggling to articulate the Guidance. That accepted they are now free to replicate this concept to other bands and setups.
2. Assessing at 20 metres is not a current priority. We have until next spring to complete docs for frequencies from 10 to 110 MHz, so my humble suggestion at present would be to do 144MHz and up and leave HF for a while and see what emerges to assist.
Hope that helps.
...and thanks for your feedback on this evening. It was a challenge to pack something as 'involved' and critical to us all into a Talk evening without racing at such a pace as to leave everyone MORE confused than they were when they came in!