Single Judge Application; Pain limits ability to function; Deluca factors; in rating musculoskeletal disabilities, the Board must rely on VA examinations that consider whether and to what extent pain, or other factors listed in 38 C.F.R. §§ 4.40 and 4.45 (the Deluca factors), limit a veteran’s ability to function. Sharp v. Shulkin, 29 Vet.App. 26, 32 (2017). If pain causes functional loss, it “must be rated at the same level as if that functional loss were caused by some other factor.” Mitchell v. Shinseki, 25 Vet.App. 32, 37, (2011). For an examination to adequately capture functional loss, the examiner must opine whether pain could significantly limit functional ability and, if feasible, portray that opinion “‘in terms of the degree of additional range-of-motion loss due to pain on use or during flare-ups.’” Sharp, 29 Vet.App. at 32 (quoting Deluca v. Brown, 8 Vet.App. 202, 206 (1995)). If an examiner is unable to offer a nonspeculative estimate of a veteran’s functional loss due to pain, the examiner must explain why such an opinion cannot be offered. Id. at 32;