Corrected version:
1. You should only be projecting sales for a 1 week over the base week. That projected week should be the next week w15. You only need to project 1 week because in step 4 it was calculated that Total Stock Weeks is 0.857 weeks (even less than 1 week)
2. The calculation that was used for the % Over Base Week was incorrect. For w15 the calc is “w15 Class Sales / Base w14 Class Sales”
3. The additional column you have added in Cumulative Unit Sales is also causing problems.
However, I suggest reviewing all the calculations/formulas I had used in the samples provided for the training, as they have been changed in these examples provided by BJC