Does an aftermarket screen really cause battery draining?

Had a customer come back today with a 6+ that the screen was replaced on a few months back. He took it into Apple because his battery is draining quickly. They wouldn't cover it because it was an aftermarket screen- they blamed the screen on the battery draining faster than usual. We only use OEM quality and have never been accused before of using 'cheap' screens. Is Apple blowing fluff to make a sale and avoiding acknowledge iOS and other issues with their phones that actually do cause accelerated battery draining.