Saaya, as you're working for a memory manufacturer, is there no way for you to test this instead of relying on the reports of xtreme overclockers?

Make a quick set-up in your lab: 5 setups all equiped with the same hardware/software and make sure all memory kits are from the same batch. First setup with 1.9, second with 2.1, third with 2.3, fourth with 2.5 and fifth with 2.7 and let them run at non-maxed-out overclocked settings 24/7. Now time how long the setups last and report back. I'm quite sure you'd do the community a big favour with it.