SNMP::NPAdmin might be helpful in pursuing an SNMP approach.
in reply to Re: Getting statistics from an attached device (printer)
in thread Getting statistics from an attached device (printer)
I've used Wireshark to avoid understanding overly convoluted web pages. It turned out to be far easier than I expected. It will help to filter on the IP address of the printer either in capturing transactions or in analyzing them. Once you know what requests are being made, you may find wget to be useful to test requests that the GUI application won't generate.