Jane,
FM won't ask. You have to click on the FM entry to see what option are available and then de-select. The default (if you do nothing) is to install the PDF Creator add-on. Neither the FM nor Acrobat installers check if there already is a version of Distiller installed. So they end up stomping all over a pre-existing Distiller installation. If you want to use Acrobat from the TCS, install that first and then install FM without the add-on.
You have to explicitly de-select the Adobe PDF Creation Add-on after you uncover it.