Ive always thought that the reason they had you list that time as SIC is because they want to know how many flight hours you have, but they really want to know how many PIC hours you have.
I guess they could change the inputs to include TT, PIC, SIC, but I think their current setup gets the job done. I dont think they are going to look at your app and ask why you listed SIC time in a baron when its a single pilot light twin. They just want to know how many hours you have and how many of those were you the signing PIC.