It does work in Excel 2016, because that's what I have, so...?
There is a recent Bogleheads thread,
Social Security “Hump” and the new tax rates??? - Bogleheads.org, in which someone noted a problem with Excel 2010.
I believe the Excel 2010 issue has to do with the FORMULATEXT function and how problems with that affect cell O82 and thus the graph scaling. One can get around that, and make updating the graph x-variable faster, using a macro attached to a button. That has the downside of causing Excel to warn people the file "contains macros." So it goes - no perfect solution (that I've found).
Because the macro will (I believe) work in Excel 2010 through 2016, while FORMULATEXT does not work in 2010, I'm planning to put the macro into the next release. Work in progress below, with
DTI = named range for cells P82:R583
U75 = cell in which one enters the desired x-axis variable. E.g., B11, or D31, or B3, etc.
V75 = cell in which one enters the desired y-axis variable. E.g., D61, or D65, etc.
Sub Macro1()
'
' Macro1 Macro
'
' Keyboard Shortcut: Ctrl+n
'
Application.ScreenUpdating = False
Application.Calculation = xlCalculationManual
'
Range("U75").Select
X = ActiveCell.Value
Application.Goto Reference:="DTI"
Selection.Table ColumnInput:=Range(X)
Range("U84").Value = X
'
Range("V75").Select
Y = ActiveCell.Value
Range("U83").Value = Y
'
Range("Q82").Formula = "=" & Y
'
Application.Calculation = xlCalculationAutomatic
Application.ScreenUpdating = True
'
End Sub
I make no pretense regarding Excel macro expertise, so any "obvious" improvements gladly accepted.