Must run macro twice for it to work (but fine on step-through)

[mitikthewalrus]

I have a short VBA macro that calls a sequence of 6 near-identical subroutines. I've provided one of them below (Year0) as a sample; the others just reference different rows on the same worksheet. If I step through AllYears it works fine to completion, but when I run it, it seems to skip the subs Year1-Year5 and says the calculation is complete without performing the actions. No error messages are given (i.e., the macro doesn't exit early), and the "t" is reported as 0. If I immediately run the macro again, it succeeds with all calculations in 0-1 sec. It consistently runs on the second click, but never the first.

I have already confirmed that "Enable Background Refresh" is unchecked. I tried inserting time delays after each sub, but that didn't seem to help, either. Calculation is automatic at the outset. Any ideas?

Excel 2013
Windows 8
64-bit

Sub AllYears()
'
' Runs base year and all five projection years in sequence
'
    Application.Calculation = xlCalculationManual
       
    Dim t As Date
    t = Now()
       
    Application.ScreenUpdating = False
    
    Sheets("USCN").Select
    Year0
    Year1
    Year2
    Year3
    Year4
    Year5

    Application.Calculation = xlCalculationAutomatic
    Application.ScreenUpdating = True
    Sheets("Output - Live").Select
    MsgBox "Calculation Complete  ( " & Format(Now() - t, "s") & "s )" 

End Sub



Sub Year0()
    
    Dim limit As Integer
    limit = 1000
    Dim count As Integer
    count = 1
    
    Range("DT120").Value = Range("AF97").Value
    Range("A105:DT124").Calculate
    
    Do While (Range("DI122") > 0.00001 And count < limit)
        Range("DI107:DR118").Value = Range("D107:M118").Value
        Range("DT120").Value = Range("AC122").Value
        Range("A105:DT124").Calculate
        count = count + 1
    Loop
    
    If count >= limit Then
        MsgBox ("No solution found for " & ActiveSheet.Name & " -- exiting macro.")
        End
    End If
   
End Sub