It would be beneficial if the approvers could view the instructions form the other approvers (assuming they have been submitted). We have our building managers as an 'approver' and it would be beneficial and more sensible if the treasurer (or any other approver) could see the instructions submitted by the Building Manager. If the BM has not approved the invoice, they make comments as to why and this is useful information for the treasurer. They would then submit a NO to pay and be aware of why it was not approved.
The Building Managers are the people on the ground who are generally the only ones that confirm the work was done and in accordance with quote and therefore approved to pay.
Transparency is critical and it should be that all approvers can see what other approvers have submitted (and comments if they have not approved).