You are disregarding the startup surge requirement. Can be as much as triple. I have even seen six times specified.
I have run into this myself with a small portable A/C. Although the inverter was rated for double the continuous amp draw, it would not start, just hummed. The quality of the AC output power is significant also.
The only thing that would save you is if the 750 watts actually IS the startup surge requirement. Possible with the newest ones, I guess.
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