Purchase Agreement workflow always goes to Primary Position of a worker though we specified the exact position.

Here is the example:
We setup the workflow approves according to hierarchy for Purchase Agreement and reports to position as below:
Hierarchy Type: Managerial Hierarchy
Start From: Workflow originator
Position Description Worker Job Title Department Reports to Position
P1 Clerk W1 Sr Clerk D1 RP1
RP1 Head of SectionW2 TL D1 RP2
RP2 Sr Manager W3 Sr Manager Last
Approval
User D1 RP3

Here W2 worker is having two positions RP2 and RP4. Here RP4 (Reports to position is Primary).
Purchase Agreement Submitted by P1 should goes to P1 -> RP1 -> RP2 but it is going to P1 -->RP1 --> RP4 (Which is Primary Reports to Position of Worker W2). Please suggest how we can achieve this scenario.