In ClarisWorks 4.0 and ClarisImpact 2.0 Fill Special does not fill correct dates when incrementing by one month and choosing a day that may not be present in all months.
Exact steps to reproduce:
1) Create a SS (In ClarisImpact create a Table)
2) Enter 12/31/95 in cell A1
3) Select row A1 through A4
4) Select Fill Special from the Calculate menu (From Table menu in ClarisImpact)
5) Choose Date increment by 1 month
The result is 12/31/95, 1/31/95, 3/2/95, 4/2/95. Fill Special can't find the end of the month and back up to it. Instead, it will fill with the wrong date for months after the first short month.
This happens with any date that cannot be found in the subsequent month. Another example would be beginning with 12/29/96, it doesn't find a 29th in February of 1997, so it drops that whole month and begins with 3/1/96 after that.
Conclusion: Using dates that range between a day number of 1-28 is safe, but this issue will show itself with day numbers 29-31 as those are days of that month that vary from month to month and year to year.