Apple has recently added back glass damage coverage to its AppleCare+ platform, which effectively lowers repair price on some services for the iPhone 13 and iPhone 12.
The support page has been updated to show the coverage as an extension for screen-only damage. Before, iPhone back glass damage carried a $99 charge for devices with AppleCare+, with screen-only repairs racking up only $29. With the new addendum, back glass repairs have been integrated into the screen-only category and are charged only $29. These changes only apply to the newly-announced iPhone 13 and iPhone 12 models.

Also, iPhone owners will be charged $59 if there’s damage to both the back glass and the screen, and as long as there’s no other damage done.
The change in pricing suggests that Apple has developed a new method or technology to replace the back glass without increased labor or parts, although it’s not confirmed.