Conditional formatting problems in my Workout Tracking spreadsheet!

[me150709]

I want to make the stats for each exercise from week 1 (weight and reps), to show up in week 2 but greyed out. This way I will see how I did the previous week as I am entering in new stats. Then once I enter new data I want that data to show up in the upcoming week but greyed out. I tried conditional formatting but that only seems to work if I use a formula to input the last weeks data. I want more of a "ghost" of the previous week, where if I enter new info it updates, but then if I delete the new info, it goes back to the greyed out "ghost" of the last weeks numbers. Any ideas on how to do this?

 

[me150709]

Link to the document

https://drive.google.com/file/d/0B_Xij6jC9QX6b0JCMzVCWWxkUVk/edit?usp=sharing