Which invoice lines does the approval rules read first?

Hi,

We are experiencing inconsistent invoice approval routing.

We have a single invoice with three invoice lines containing different dollar amounts, and it is meant to go up the job level hierarchy until it is approved by someone with the authorized dollar threshold amount.

In some events, it is going to the right level (e.g., it is starting at job level 10 and will climb until it is approved by a job level 40). In other events, it is going straight to the job level 40, without first seeking approval from the individuals with the lower job levels.

The invoice has the same information, same supplier, amounts, etc. The only thing we are changing is the line description - hence we are wondering if the approval rules are reading these line descriptions alphabetically?