You usually want an equal voltage and equal or higher current.
A higher voltage is bad, but in this case, it is only ½V higher, so it is unlikely to damage the system, especially since most sophisticated electronics power-supplies are usually designed to take a small variation up or down because not everybody uses a UPS, so they need to accommodate dirty power-lines (to a point).
That said, the flicker you are seeing is likely due to the replacement power-adapter being unable to provide the full draw that the original one can. The difference in current is fairly small and the adapters are usually rated for at least a little more than the device’s maximum draw, but if they had provided the laptop with an adapter that provides just barely enough (e.g., it was cheaper than a more powerful adapter), then an replacement that provides even slightly less may be coming up short and causing the screen to dim or flicker for a moment when you plug it in and the charger momentarily spikes.