Formula could be:
If(Lower(Trim([Customer - Enrollment - Meter Number] & ""))
<> Lower(Trim([Customer - Meter number] & "")),
"Mismatch")
To display only mismatched records, create a report and set the Filter to where that formula field = Mismatch. This assumes you have entered both meter ID's. You may want to check for incomplete data also:
If Trim([Customer - Enrollment - Meter Number] & "") = ""
OR Trim([Customer - Meter number] & "") = "",
"Missing Meter Info",
If(Lower(Trim([Customer - Enrollment - Meter Number] & ""))
<> Lower(Trim([Customer - Meter number] & "")),
"Mismatch"))