Capture wim file size - Hyper-v snapshots

Rcently I needed to create new gold (reference) image based on Windows 7 x64 with Office 2013. I used Hyper-v VM, fully updated both office and windows and create some snapshots during this process. At the end I manually run sysprep and then use imagex /capture to get wim file with image. The size of caputerd wim file was first about 14GB - then I tried to remove all snapshots (first exported VM as a backup of my job) and did the capture process once again - now the size of wim is 11GB