I don’t have the same case, but I am curious what office the case was transferred? Because the only processing dates to estimate you can see online when an I-751 case will be done is in the service centers CSC, NSC, VSC, and TSC. The offices do not post processing dates for I-751; if I were you I would call USCIS to clarify this. If you have to keep checking processing dates with VSC although the case is at a USCIS office that is a good new, it means your case was transferred to be solved faster since they have too many cases at VSC office now. An Immigration officer told me when I went to stamp my passport, that a case is transferred to an office when the SC has too many cases and need help with offices to solve them faster, she mentioned office no SC because mine was transferred from TSC to VSC on March 2008 and still waiting, yours was transfered to an office that is faster. Good luck.