Md said not to worry about low (7.5) free psa. Is this true or should I see a urologist? 60yrs. Normal psa for age.

This. This really depends on what your total psa is. If your total psa is between 4 and 10 it is more significant as the lower your free psa, the higher the likelihood of prostate cancer. If your psa is less than 4, the free psa is really not that important.