Lightweight association of virtual components

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For example, I am separating FCC gasoline into light and heavy fractions. It is known that about 30% of the light components in FCC gasoline can be fed into the process, and the D86 value of the entire FCC gasoline is also known. Through calculations, it can be determined that when the overhead yield (D/F) is 40%, the separation results show that almost all of the light components end up in the overhead product; the remaining components are the virtual components starting from PC47. My question is: when entering these virtual components, there is an option labeled “Optional”, under which there are two checkboxes: “Apply cracking correction” and “Match light ends with distillation curves”. I didn’t select either of them, and the calculations I got seem reasonable, fairly accurate compared to experimental values. I believe that the actual calculation of the light components already takes into account the D86 value. The problem is that whenever I select “Match light ends with distillation curves”, the system gives an error. I would like to ask the experts here – could anyone explain the underlying calculation methods used, including the thermodynamic properties employed? What do these two checkboxes mean? Thank you