Assignment level DFF update based on Employee Job level DFF and Employment Category

Summary:

Based on one assignment level field "JobID" defaulting the Assignment DFF Attribute_Number_1 (AIP TIER%) logic works.  

But when we add logic to nullify the field based on Employment category (Parttime) to refresh the same Assignment DFF (AIP Tier%), it doesn't work, and also it doesn't blank out (nullify) the DFF value if Assignment category is temporary, thought condition is added to logic to assign DFF field the value to NULL if Employment category is Parttime Temporary.
Please advise on how to refresh the assignment DFF based two assignment level fields, whenever Job is updated and tab-out, also Assignment category is update and tab-out refresh the Assignment DFF AIP Tier%