Some things to check:

1. Open the main form in design view.
Right-click the edge of the subform control, and choose Properites.
Examine its Name property (Other tab of Properties box.)
You may find the Name is different from the SourceObject.
That is the name of the subform control may not be the same as the name of
the form loaded into it. You must use its Name (not the name of its
SourceObject) in the Control Source of Text154.

2. You have a text box in the "footer" of the subform. Is this the Page
Footer section? Or the Form Footer? It must be in the Form Footer. The
Control Source is right for the field described above. It may help to again
set the Format property to Currency. Then open the subform directly (from
the database window) and check that the total shows correctly when you have
the form in Continuous view.

3. The subform is populated from a query. I wasn't clear if the Extended
field was in the query, or just in the Control Source of a text box on the
subform. If it's not in the query, add it there by typing the expression
into a fresh column in the Field row in query design:
   Extended: [Labor_Charge] * [hundredtime]
or possibly:
   Extended: CCur(Nz(Round([Labor_Charge] * [hundredtime], 2), 0))
Then set the properties of the text box in your form to:
   Control Source    Extended
   Name                 Extended
   Format               Currency

4. If it's still not solved, try temporarily removing all other calculated
controls on the form. This eliminates the possibility that the problem could
be elsewhere.