I found something VERY interesting tonight. In the Workshop Manual - the one the dealers use, not the Owner's Guide (OG) - the instructions for doing the DPF regeneration after the amber warning are pretty much the same, word for word in fact, as they are in the OG.
But there's also an extra instruction. The manual advised that you drive for a further 10 minutes to ensure the DPF is properly cleaned.
That definitely does NOT appear in the OG.
Note this was for the 3.0d, MY2010-2013 XF.
There's also a section that tells you that "active regen occurs automatically every 450 miles (adjusted according to driving style)", but a few pages and a couple of years later that was rewritten to read "every 250 miles" .