Can somebody explain why ReferesTo works in column A and Not in Column B

LastRowA = .Range("A" & Rows.Count).End(xlUp).Row
Set NameRange = .Range("A1:A" & LastRowA)
NameStr = Mid(NameRange.Name.RefersTo, 2)
Set DateRange = .Range("B1:B" & LastRowA)
DateStr = Mid(DateRange.Name.RefersTo, 2)