Generic Solar System. Solar field thermal output

Dear Paul,

Thank you for the clarification.

But I wanted to ask about this equation, too, that I have seen that it has been applied in the program:
[("Solar field thermal output")-("Solar field thermal losses")]*("Solar field optical efficiency")= ("Solar field delivered thermal power")

I do not understand why the "solar field thermal losses" have been applied before to the "solar field optical efficiency".

Maybe, this equation would have to be as I write it now:
("Solar field thermal output")*("Solar field optical efficiency")= ("Solar field delivered thermal power")-("Solar field thermal losses")

Thanks in advance.