Logging Sic question

[Pantera]

question is about logging SIC in a business jet that requires a pic and an sic. I understand that because the sic is required you can log it as sic. But what happens if you are the sic and now the pic in the same jet has a single pilot type rating in the same jet. Can you now still log sic since technicaly you are now not required.

thanks and happy flying