Jacket warpage is often so severe that the disk cannot be rotated. Very stable ABS material was originally used to manufacture rugged shells with ample wall thickness. Cost pressures have resulted in reduced wall thickness. Less expensive substitutes are being used for ABS, and some give excellent performance. Other substitutes can warp, especially during transportation or storage at elevated temperature and humidity conditions.
Clip level is irrelevant.
Only special tests and assurances from the manufacturer can indicate archival quality. Tabs of the proper thickness using dimensionally stable plastics will maintain proper torque and cleaning action for many years. Pricing pressures can result in thin lifter tabs or the use of less expensive, dimensionally unstable materials. Clip level is not closely related to lifter tab quality. Again, special tests and representations by the manufacturer are the answer.