Just had a look in "Mosquito" by Sharp and Bowyer, which is pretty much the Bible of All Things Mossie.
It says that seven Mosquito squadrons on anti-Diver ops full-time (includes 96, 219, 409, 418, 85 and 157 squadrons, I believe 605 is the other one) claimed 471 flying bombs, with "part-time" anti-Diver squadrons (must include 456, 25, 68, 264 and various other squadrons, along with assorted HQ, Station, and at least one Operational Training Unit aircraft) claiming another 152. This corresponds to the 620 given in the video referred to above.
Part of the confusion may result from the fact that as of 5 July 1944, V-1s destroyed over land only counted as half an enemy aircraft destroyed - over the sea it was a full e/a. Don't ask me how this affects numbers reported for Tempests and the like - since they are Not Mosquitos I don't care.