Can a pwm solar cc generate 750w solar power with only 40A current?

Hello

I don't know much about solar stuff.. I have been researching a lot lately on the topic. I stumbled upon this solar inverter on ebay
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**broken link removed**

It has a pwm charge controller but what interests me is that with only 40A current 750W panals can be connected...

As far as i understood the system so far... suppose the efficiency is 100%
With pwm cc and 12v battery... 12x40 = 480W max output
for 750w ... 750/12 = 62A so charge controller needs to be rated at about 70A ...
I am talking about the system 850VA 12V

Am i calculating it incorrect ...?

Again i am new to all these solar..things...

Please help me understand this...

Regards!!