Dx and treated b12 def with lvl of 78 five yrs ago, but now ferritin 13 (12-250ug/l) and folate (folic acid) 6.3 (4-20ug/l), should these levels b supplemented?

Iron: There is certainly no harm in supplementing your folate (folic acid) (must continue your b12!) but that level seems fine. Your ferritin level seems low and most likely indicates that there is not enough iron in your system. This too can lead to anemia. Iron supplements seem indicated. You should see your doctor to fully evaluated why your ferritin is low.