Sony has confirmed that it won't allow PS Plus and PS Now subscriptions to accumulate time

In recent days, PlayStation Plus and PlayStation Now subscribers have begun to report the inability to activate prepaid code cards if the subscription is already valid.
And the company has confirmed that this is not a bug, but an official ban.In the Q&A section of the official PlayStation Plus page, it was reported that subscription vouchers cannot be activated until the current subscription expires or until an updated service is launched in the region.
In this way, the company wants to prevent the accumulation of prepaid subscription time before the introduction of changes in payment terms.As we already know, from June 22 in Europe begins an updated version of the PS Plus subscription with three payment levels: Essential, Extra and Premium.
All existing subscriptions will be automatically switched to the PlayStation Plus Premium model.When it expires, players will be able to choose the appropriate model and pay for it at the new rates, including prepaid card.