CSWP Sample Problem Segment 1 Mass Properties Error

Hello,

I am attempting to complete the sample question given by Solidworks for Segment 1 of the CSWP certification. I am able to answer question 1 correctly and obtain a part mass of 14207.34g. However, the second question asks you to update the parameters and enter the mass again. I have used global variables and simply updated them in the Equations table (exactly how I saw it done on a video solution) but my problem is that I get the wrong mass when I update my parameters. Furthermore, if I change my parameters back to the original ones, I don't even get the same answer that I first got with the original parameters. I cannot figure out if I have done something wrong or if it is a bug. I am running the Student Solidworks 2016 on Windows 10. Everything else seems to be working perfectly. Has anyone had this problem and/or have any idea what could be the problem? Thank you,

Hashim