Many errors from layer change

I use these blanks for months and had only 2 Examplaren (25) no problems. After firing (with 4-fold safety's sake with LiteOn BD burner) I scan the error stehts still with OpriDriveControl.
In almost all blanks while the PIE-error rate (correctable error) rose after layer change from green to red, and always more than 700 / sec, which is alarmingly high.
Thanks to the error correction, the player (also of that in the PC), the error rate of the uncorrectable error (PIF) still remains low, ie in practice is likely to be a proper player (laser not old and optimally adjusted) after the LW have no problems.
BUT: There is here no more reserves upwards, already an aging of the laser or misalignment or pollution can lead to significant problems. Too bad. I must have it grab again to the expensive Verbatim where (almost) never was the case.