Honestly? I think you got rotten directions from an underpaid call center worker.
Because truthfully I have never, ever heard this before. And apparently nor has anyone else on this forum.
Edit:
Health Insurance Plans | Blue Cross and Blue Shield of Texas
2016 INDIVIDUAL AND FAMILY PLANS
BLUE ADVANTAGE HMO / BLUE ADVANTAGE PLUS HMO
Preventive Services
Many long-term illnesses can be prevented or managed when found early. With the Affordable Care Act, most health insurance plans must cover a range of preventive services with no out-of-pocket costs like a copayment or coinsurance. Services include certain screenings, immunizations, and other types of care, like:
Flu and pneumonia shots
I think you need to blame the call center worker for this one.