Depending on the amplifier. If the amp has an output transformer than theoretically it delivers the same wattage to the both loads if the transformer designed so.
If the amp is direct-coupled and has also rating to lower wattage(s) than it's also OK to take lower impedance speaker.
Usually direct-coupled SS amps are even better with lower-impedance loads and cripples on the high impedance loads. The opposite with direct-coupled tube amps(OTL).
If the amp is direct-coupled and has also rating to lower wattage(s) than it's also OK to take lower impedance speaker.
Usually direct-coupled SS amps are even better with lower-impedance loads and cripples on the high impedance loads. The opposite with direct-coupled tube amps(OTL).