Problem querying datetime in SQL Server

[Terri]

Access 2002 with linked tables to SQL Server 2000

I have a query that uses 2 unbound form fields as criteria.

This returns unexpected results.

Between IIf([forms]![frmreporting]![startdate] Is
Null,#1/1/1900#,[forms]![frmreporting]![startdate]) And
IIf([forms]![frmreporting]![enddate] Is
Null,#1/1/9999#,[forms]![frmreporting]![enddate])

This seems to work
Between IIf([forms]![frmreporting]![startdate] Is
Null,#1/1/1900#,[forms]![frmreporting]![startdate]) And
IIf([forms]![frmreporting]![enddate] Is
Null,#1/1/9999#,[forms]![frmreporting]![enddate]+1)

Is this reliable?