I think this is probably due to difference in how they sense room temperature, rather than cooling.
All the splits i tested, majority of different brands show different cooling at same thermostat setting.
Tier 1 Top brands actually keep room temperature same as set point, whereas Chinese brands keep room temperature 1-2C less than set point, giving people the psychological illusion that they are providing more cooling than Tier 1 brands.
Always felt Tier 1 Top brands ACs cooling less than Tier 2 brands on same thermostat setting in my personal experience.