Hmm . . . I hadn't seen that in the manual (page 122).
I don't see the sense of it. If the soot loading happens to be too low to require regen and the driver has no indication when it might be required.
Seems silly to require randomly revving up in the hope of a regeneration
Regen takes about 6 minutes at 100km/h on mine (6th gear 1800-2000 rpm). Usual trip is about 20 minutes.