Data Validation hide previously used dropdown list

Hi everyone,

I am trying out some data validation formulation in my workbook with the reference to www.contextures.com setup guides on DV0016 & DV0047.

However, my range of data from AA7:AG7 returns value = 0, it suppose to returns the similar value with AA6:AG6, and I can't find the mistake i did.

Meantime, the dropdown list at H7 only presents "0" listing. Thus I can't continue with J7, L7 & N7. The subsequent value at J7 should be offset the value present at H7.

Can anyone enlighten me on this data validation issue?

Many thanks in advance.