Problem with interpolating data

I have a problem with interpolating. When the residuel of a data point (polyline-data point) is 2x standard deviation (allready calculated), then I want reject the data point and it appears red, "rejected" and thick. Then I want to interpolate with the previus and next datapoint.

When 2 datapoints are rejected after each other this no longer goes. When this is the case I want to replace the data point with the polyline value.

I tried to make something, but it runs stuck.

'Now interpolate through

CheckedRow = Headerrows + 1

Do While CheckedRow < NumRows

    'Set variables
    checkedKP = Cells(CheckedRow, KPColumn)
    CheckedValue = Cells(CheckedRow, AfterRejectionEColumn)
        
    If CheckedValue <> "Rejected" Then
        'Leave as is
        Counter = 1
                
    ElseIf CheckedValue = "Rejected" Then
        
        LastgoodKP = Cells(CheckedRow - 1, KPColumn)
        LastgoodTop = Cells(CheckedRow - 1, EastColumn)
        LastGoodRow = CheckedRow - 1
        
        NextgoodKP = Cells(CheckedRow + 1, KPColumn)
        NextgoodTop = Cells(CheckedRow + 1, AfterRejectionEColumn)
        
        Interprecords = (NextgoodKP - LastgoodKP)
        Topdiff = (NextgoodTop - LastgoodTop)
        
        Cells(CheckedRow, AfterRejectionEColumn) = (Counter + 1) * ((Topdiff * (checkedKP - LastgoodKP)) / Interprecords) + LastgoodTop
       
       If CheckedValue + 1 = "Rejected" Then
        Cells(CheckedRow, AfterRejectionEColumn) = Cells(CheckedRow, PolyEColumn)
        
        Counter = Counter + 1
    End If
    End If
        
    CheckedRow = CheckedRow + Counter ' Move on as many as required to get next non rejected value
Loop