These are essentially normal values, regardless of whether the forced expiratory volume in the first second/forced vital capacity (FEV1/FVC) ratio is 85% or the ratio is 85% of predicted. It is common to have values that are over 100%. Your low nighttime oxygen levels have everything to do with apnea and nothing to do with your spirometry.
From what I've read, a low RV number along with the other numbers that are normal means a restrictive lung disease. Have you had a CT scan? If not, I'd request it. Your DLCO is actually pretty good-slightly below normal. The RV at 70, to me is more concerning, and the CT will probably give you the answer.
Hopefully the doc will answer you soon and will suggest other tests that you can look into!!
Good luck