The Hardware Universe under Field Replacement Unit Parts has 2 PSUs for the FAS2554 https://hwu.netapp.com/Controller/Index?platformTypeId=2032#none
Mktg Part No Mfg Part No Description
X518A-R6 114-00070 PSU W/Fans,580W,AC,DS4243/4246,FAS2240-4
X522A-R6 114-00026 PSU W/Fans,580W,AC,Energy Star,DS424x
It also has the same 2 PSUs for the DS4246 https://hwu.netapp.com/Shelves/Index?osTypeId=2032#none
Mktg Part No Mfg Part No Description
X518A-R6 114-00070 PSU W/Fans,580W,AC,DS4243/4246,FAS2240-4
X522A-R6 114-00026 PSU W/Fans,580W,AC,Energy Star,DS424x
It therefore looks like both PSUs from the FAS2554 can be used for the DS424x shelves.
Cheers.