How to restrict net renaming to specific cell instances in layout using SKILL?

I'm using a SKILL procedure to rename power and ground nets (vnn! to vnn, and vpp! to vpp) for instances in my layout. The layout contains three cells: "a", "b", and "c". I want the renaming to apply only to instances of cells "b" and "c", but my current code is also applying changes to "a" unexpectedly.
 

I suspect the condition is not filtering correctly. Could someone help me correct the logic so that the renaming only applies to "b" and "c"?
I'm using cadence virtuoso 23.1 version

Thanks in advance!

Code:

procedure(renamepwrandgrndnets()
let((cv instTerm netObj netName)
cv = geGetEditCellView()

foreach(inst cv~>instances
when(or(equal(inst~>cellName "b")
equal(inst~>cellName "c")
)
printf("Checking instance: %s\n" inst~>cellName)
instTerm = inst~>instTerms
foreach(term instTerm
netObj = term~>net
netName = netObj~>name
printf(" Terminal: %s, Current Net: %s\n" term~>name netName)
cond(
(netName == "vnn!"
printf(" Renaming net '%s' to 'vnn'\n" netName)
dbRenameNet(netObj "vnn")
)
(netName == "vpp!"
printf(" Renaming net '%s' to 'vpp'\n" netName)
dbRenameNet(netObj "vpp")
)
(t
printf(" Net '%s' is not vnn! or vpp!, skipping.\n" netName)
)
)
)
)
)
)
)