Yes, ApprovalMax does support routing for several NetSuite custom fields.
The field types Checkbox, Number and Reference are supported. In the approval matrix, Organisation Administrators can specify rules based on such NetSuite custom fields set in ApprovalMax.
Here is how it's done
In the main menu, find your Organisation and go to Approval workflows under Workflows and settings.
Open the relevant approval workflow:
In the respective step, open its approval matrix by clicking on the Matrix icon:
Click on Add a field and select one of the predefined custom fields:
Then, set up a rule and values for the field:
Click on DONE to save your changes.
Please note: It's not possible to delete custom fields if they are used in the approval matrix.