Need fuse operation and interchange info

[helpful55]

I have an excessively basic question, but I would like to get definitive info. I am working with an AC power amplifier. The manufacturer calls for a 4A 110v sloblo or a 2A 220v sloblo fuse in applicable countries for the same circuit. My understanding is that a fuse blows due to total wattage, not the actual amperage flow since that depends on the operating voltage, so both of those fuses actually protect the circuit equally. Is that accurate, and also while it may not be technically wise to use the 110v fuse with 220v supply, can't the 2A 220v fuse also be properly used in the circuit? Thank you for any help.