Override default value sourced via Dlookup?

[CW]

I have a Quotes table and form, and a Costing form which is based on the
CostsActual table.
On the Costing form I want the various components of our costs to display
the quoted amounts by default, but if these have actually come out different
once we have done the job then the user needs to be able to override the
figures and enter the actual costs.
The source of each Cost control is the relevant field in the CostsActual
table.
In the Default Value properties of these controls I have used DLookup to
pull the quoted costs from the Quotes table and that's fine. However,
although they show as Enabled Yes and Locked No, we cannot overwrite the
displayed amounts.
Am I asking too much, to be able to show a value pulled from one source by
default, but then overwrite it with another value that is input by the user
and which writes to a different table (albeit the table which is the source
for the form)?
Thanks for any suggestions!
CW

 

[CW]

Many thanks for your prompt reply...yes I do have the Control Sources set,
they point to the relevant fields in the CostsActual table.
That's cos the way I want it to work, users will initially (by default) see
the quoted amounts which are being pulled from the Quotes table. But if the
actual amounts have come in different, they need to input those and have them
stored in the CostsActual table. In this way, we can work out variances
between amounts allowed for within our quotes (stored in the Quotes table and
not overwritten) and the actual cost amounts (newly stored in the CostsActual
table).
Hope this clarifies what I'm trying to do, and why. The question now is, HOW
?!
Thanks again
CW

 

[CW]

OK thanks, I'm clear about what you're saying.
What I have is a combination of both.
On each of the Cost controls the Default Value is set to a DLookup in the
Quotes table, and at the same time the Control Source is set to a field in
the CostsActual table. The source for the form is that table itself, it's not
via a query.
So, should it be feasible for us to overwrite the displayed default value
and write the desired new amount to the CostsActual table? It's not possible
as it stands now.
Thanks
CW

 

[CW]

Bob, thanks for your suggestions...yes, all other controls on the form are
editable, it's just those that have their Default Value set to DLookup that
are giving the trouble. And yes, the Allow Edits property is set to Yes. And
no, I'm not using a query as the source for the form, it's based directly
upon the CostsActual table.
I wonder if you have any further thoughts...?
Many thanks
CW