Honestly, for a learning party it is ok to use the LB on adds. Even if the group as a whole does not have the required dps to finish the battle, at least it will give people experience post adds. Honestly, it can easily boil down to 1 dps holding a learning party back from clearing adds phase. I was in a learning party that couldn't clear adds and after 40 minutes of wiping to adds we learned that the NIN only had around 500 accuracy. After learning this, we dropped the instance and then helped the NIN by explaining why they needed ACC. A few people helped him spend his Esoteric and Lore tomes to raise his accuracy without hurting his other stats too much and I bought a HQ i220 crafted item and melded some materia onto for him. Another person made some HQ accuracy food for them and we went back in. First attempt we cleared adds with no problem and were able to get some Fang and Claw and beyond practice in.