I just got this this one and pretty pleased with it. Ho-hum cellphone photo will have to do for now. 18mm 3.32g.
The D6 bust (and associated "MAX" legend) is unlisted for this P-captives-L issue, although Lech's "Not in RIC" has another example, plus one with a D5 bust (Same helmet as D6 but draped).
RIC does have a misdescribed D6 bust (RIC 63 - listed as D2) for the (earlier?) captives-only issue.
It's interesting to see the mix of H11 (high-crested decorated helmet) and D6 busts at the various mints during the VLPP type. Some used both, some primarily one or the other.
The Trier billion series of 313 AD (that the reintroduced VLPP is based) on had an H11L bust and PTR mintmark. So, it seems that in 318 AD Trier, now using two officinas, understandably wanted to avoid confusion between the earlier 20% silver coin and the new 5% silver one, and did so by:
1) Avoiding the H11L helmet for the early issues
2) Avoiding officina "P" for the early issues
RIC VII Trier 208A (which is basically the 313 AD billion coin) does have an R5 officina "S" listed (which would have to be non-billion), although I have my doubts whether it's official if not mis-read.
RIC VII Trier 208 (with D6 bust) does have an R5 officina "P" listed, although I've never seen one. It also seems suspect.
Lyons seems to have compensated for Trier's avoidance of the high-crested helmet by going the opposite way and using it almost exclusively, which is what makes these scarce D6 busts interesting.