I went out for the first time today with my new Xp Deus. Several programs use 90 as a preset for ground balance. When I use pumping or tracking my Deus runs between 75-77. Is this low to medium mineralization. Am I better off setting it in manual and running 90. I noticed when I would get to very high iron infestation soil the number would start pushing the upper 80's but would settle back down into the 70's when I would get out of the bad stuff.