I do know there is some guidance in cfr 38 part 4 that lays out some rules on when PFT's are not required.
conditions in this section which under certain circumstances also establish entitlement to special monthly compensation.
(d) Special provisions for the application of evaluation criteria for diagnostic codes 6600, 6603, 6604, 6825-6833, and 6840-6845. (1) Pulmonary function tests (PFT's) are required to evaluate these conditions except:
(i) When the results of a maximum exercise capacity test are of record and are 20 ml/kg/min or less. If a maximum exercise capacity test is not of record, evaluate based on alternative criteria.
(ii) When pulmonary hypertension (documented by an echocardiogram or cardiac catheterization), cor pulmonale, or right ventricular hypertrophy has been diagnosed.
(iii) When there have been one or more episodes of acute respiratory failure.
(iv) When outpatient oxygen therapy is required.
I did notice that 6602 is not in that list so It appears it is not and absolute requirement, only to be waived for one of the reasons below.
I would politely ask your DAV rep why they are adding unnecessary requirements to the ratings process, It sure seems to me your doc should fill out the DBQ, note your steroid treatments sign it and hand it back to you. Your DAV rep when forwarding it should point out that a PFT is not a requirement and that per the enclosed DBQ completed by Physician X, Mr Vync has had x number of sterodial treatments for his asthma over the last year.
Next thing you know they will be telling Amputees that we can't rate them because we can't get an acurate ROM!