Asthma or COPD?

I am a 57 year old male, smoked 30 years, worked 30 plus years in the automotive factories - machinist 7 years, millwright 5 years. Diagnosed with asthma in 2000 after hospitalization twice - 9 hours and 4 days. Suspect was "coolant - chemicals & grinding dusts and various other chemicals". I continued working in the shop for 3 years, intending to go back to school nights and upgrade, for a career change, compant went bankrupt.
Apparently it is now chronic - very short of breath on little exertion, 3 medications.
Fighting a workmen's compensation case, for 5 years, working at a job paying less than half I made before.
**Question: which expert is correct. Spirometry says - 83% of predicted - USING 3 DIFFERENT DRUGS**(Obviously they bring the percentage UP??
Family Doctor believes it all smoking related, various other Dr's have varying opinions - ALL said to find other work in a clean environment.

[National Jewish Health]

You could simply have asthma, but it is likely that you have chronic obstructive pulmonary disease (COPD) due to the cigarette smoke and your occupational exposures.  The distinction between asthma and COPD might be important to your workmen's compensation claim.  To make that distinction would require, at minimum, more complete pulmonary function tests (PFTs) than the simple spirometry you cite.  If it is COPD, there is no good way to apportion the contribution of smoking and industrial exposures to the COPD, with any accuracy.

The figure, 83% of predicted is not interpretable, without specification of which measure of pulmonary function it is:  forced vital capacity (FVC), forced expiratory volume in first second (FEV1) or FEV1/FVC ratio.  You are right.  If the medicines are effective, they would improve any of the values, and that would be a good thing.  83% of any of the 3 values, FVC, FEV1 or FEV1/FVC ratio, would be within normal limits.  That impairment of pulmonary function does not square with your description of "...very short of breath on little exertion."  There could be reasons, some heart and some lung, other than asthma or COPD, for your shortness of breath.  If present, those need to be identified and treated.  All of this needs to be clarified, ideally by a lung specialist.

Good luck.