[AccessD] Append query question

The following append query works fine:

 

INSERT INTO [tbl Cum Oil Test] ( [Well Name], [Date], [Cum Oil] )

SELECT [tbl Monthly Oil Test].[Well Name], [tbl Monthly Oil Test].Date,
[tbl Cum Oil Test]![Cum Oil]+[tbl Monthly Oil Test]![Prod Oil] AS [New
Cum]

FROM [tbl Monthly Oil Test], [tbl Cum Oil Test]

WHERE ((([tbl Monthly Oil Test]![Well Name])=[tbl Cum Oil Test]![Well
Name]));

 

However if I change the query as follows it will not run. I get a
message of "You tried to execute a query that does not include the
specified expression 'Well Name' as part of an aggregate function". Is
it not possible to do this in one query?

 

INSERT INTO [tbl Cum Oil Test] ( [Well Name], [Date], [Cum Oil] )

SELECT [tbl Monthly Oil Test].[Well Name], Max([tbl Monthly Oil
Test].Date), [tbl Cum Oil Test]![Cum Oil]+[tbl Monthly Oil Test]![Prod
Oil] AS [New Cum]

FROM [tbl Monthly Oil Test], [tbl Cum Oil Test]

WHERE ((([tbl Monthly Oil Test]![Well Name])=[tbl Cum Oil Test]![Well
Name]));