Confused

• FEV₁: 90% predicted
• FVC: 103% predicted
• FEV₁/FVC: 69.03%, with a GLI LLN of 0.693 (using my physician’s GLI reference values, not GOLD) I
• FEF 25–75: 64% predicted, above my LLN, with a 14% improvement post-bronchodilator
• FEF 50: increased 23% post-bronchodilator
• PEF: 114% predicted

All values are post-bronchodilator. I quit smoking six months prior to this test.

My physician mentioned that my shoulder width (18 inches) and sitting height may indicate larger-than-average lung volumes. Is this a recognized consideration in spirometry interpretation, and can body proportions such as shoulder width and sitting height be associated with higher FVC or lung capacity relative to height?

Additionally, could a relatively lower—but still above-LLN—FEF 25–75 be explained by recent smoking cessation (six months) and ongoing small-airway recovery, rather than fixed airway disease?