Macro range of cells change

Also, Right(pair, 1) = 15 is trying to compare the last string character (i.e. "5") with the number 15. You need:
Right(pair, 2)="15" to compare string characters.

Any wrong in this makro

Sub master2()
Application.ScreenUpdating = False

Dim pair As Variant, accumulator As Variant
Dim findFifteen As Double
Dim remainder As Long, found As Long

found = 1

For Each pair In Range("B30, F30, J30")
   ' If Right(pair, 1) = 15 Then 'this is wrong
    If right(pair,2) =15 then
        If pair.Offset(0, 2) <= 12 Then
            findFifteen = pair.Offset(0, 2) / 12
            remainder = 0
        Else
            findFifteen = 1
            remainder = pair.Offset(0, 2) Mod 12
        End If

        For Each accumulator In 
'??? What this "{a14,b14, not data in your picture
Range("A14, B14, C14, D14, E14, F14, G14, H14, I14, J14, K14, L14")
            If accumulator.Offset(-1, 0) = Val(Left(pair, InStr(pair, "-") - 1)) Then 
                accumulator.Value = accumulator.Value + remainder
            End If
            accumulator.Value = accumulator.Value + findFifteen
        Next accumulator
    Range("E" & found).Value = pair
    found = found + 1
    End If
Next pair
End sub

Re:Right(pair.Value, 2) = 15 .....--->...Error
Must be:
either:
Val(Right(pair.Value, 2)) = 15
or
Right(pair.Value, 2) = "15"

Post a sample file including the current macro code you are working with.

The code below will do as indicated in post #7; but, I don't understand what you are doing with the accumulator in the original code. Rows 13 & 14 don't match up with the descriptions.

Sub PartII()
    Dim SearchRange As Range, _
        DashPair    As Variant, _
        PairParts   As Variant, _
        SearchVal   As Variant, _
        FoundPos    As Variant
        
    Set SearchRange = Range("E1:E12")
    
    For Each DashPair In Range("B30, F30, J30")
        If DashPair.Value <> "" Then
            PairParts = Split(DashPair, "-")
            If PairParts(1) = "15" Then
                SearchVal = DashPair.Offset(rowoffset:=1).Value
                
                On Error Resume Next
                FoundPos = Application.WorksheetFunction.Match(SearchVal, SearchRange, 0)
                
                If Not FoundPos Is Nothing Then
                    PairParts(1) = PairParts(1) + 1
                    PairParts = Join(PairParts, "-")
                    SearchRange(FoundPos).NumberFormat = "@"
                    SearchRange(FoundPos).Offset(columnoffset:=1).Value = "" & PairParts & ""
                    
                    DashPair.ClearContents
                End If
            End If  '15 found
        End If
    Next DashPair
End Sub

I've modified the code to put repeated values from row 31 in the first empty column to the right of E in the matched row.

Sub PartIIb()
    Dim SearchRange As Range, _
        DashPair    As Variant, _
        PairParts   As Variant, _
        SearchVal   As Variant, _
        FoundPos    As Variant, _
        NextCol     As Long

    Set SearchRange = Range("E1:E12")
    For Each DashPair In Range("B30, F30, J30")
        Err.Clear
        NextCol = 1
        If DashPair.Value <> "" Then
            PairParts = Split(DashPair, "-")
            If PairParts(1) = "15" Then
                SearchVal = DashPair.Offset(RowOffset:=1).Value
                
                On Error Resume Next
                 Set FoundPos = SearchRange.Find(SearchVal, LookAt:=xlWhole)
                If Not FoundPos Is Nothing Then
                    FoundPos = FoundPos.Row
                    ' find first empty column right of E
                    While SearchRange(FoundPos).Offset(ColumnOffset:=NextCol).Value <> ""
                        NextCol = NextCol + 1
                    Wend
                    
                    PairParts(1) = PairParts(1) + 1
                    PairParts = Join(PairParts, "-")
                    
                    With SearchRange(FoundPos).Offset(ColumnOffset:=NextCol)
                        .NumberFormat = "@"
                        .Value = "" & PairParts & ""
                    End With
                    
                    DashPair.Resize(ColumnSize:=3).ClearContents
                End If
            End If  '15 found
        End If
    Next DashPair
End Sub