Because you're using DollaText, the field output is text and you'll not be able to use the bookmarked result as the input to another formula. However, a change to the field code will allow you to overcome that. Simplify the calculation and embed it in its own field, thus:
{={=settlefee*0.75-costs \# 0.00} \*DollarText \*Upper }
and bookmark the portion in red. Note that the braces (ie {}) ecompassing the red portion are field braces, which you create via Ctrl-F9.

Alternatively, create a SET field to hold the calculation and refer to the SET field's bookmark for both purposes:
{SET Result {=settlefee*0.75-costs \# 0.00}}
{REF Result \*DollarText \*Upper} - for the existing output
{=Result-Support \*DollarText \*Upper} - for the additional output

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]