Approval limits in Job level Hierarchy for Invoice approval

Summary

Unexpected results for Job level hierarchy for Invoice approval

Content

I am trying to understand the approval process.  Here is what we have:

8 job levels: 1 ($0 to $1000), 2 ($1000 to $5000), 3 ($5000 to $25000), 4 ($25000 to $50000)

Emp2 is level 2, with supervisor Emp4

Emp4 is level 4 with supervisor Emp5

and so on.

Created an invoice for $6000 with the expectation that Emp4 would have to approve after Emp2 but this was not the case.  Invoice was final approved by Emp2.

Note: an invoice for $26000 was final approved after Emp2 and Emp4 approved.  

Can someone confirm if the first scenario is standard functionality.  I would have expected Emp4 needed to approve the $6000 invoices because Emp2 does not have the authority.