HI Mark

The welding operators themselves would not be required to take further performance tests if filler is changed and the rest of the production work falls within the scope of their initial performance qualification.

The ER80 and ER90 fillers may not be typical prequalified fillers to match your base metal, which is not what you asked, but I thought to mention it anyhow.

If your WPS's are prequalified than it's important that the filler and base metals are compliant with table 3.1.    If they are not, a new WPS would need to be prepared with supporting PQR's in compliance with clause 4.