I thought that you make C/F check sheet more early.
Because purpose of C/F check sheet is to check C/F.
So I consider that it is better to create C/F check sheet before Co-check C/F .
And if C/F is created in SANWA-JAPAN, I'll check C/F at SANWA-JAPAN.
In that case please create C/F check sheet while CF is staying in Japan.
※S-cab is also the same