Yup.  Ultimately, that is what I have had to do.

Lacerte seems to create a strange number for the deduction amount based on whatever you type for the FMV of the donated property.  I don't know how it generates that number, though the number varies depending on whether you select high or low (or something like that).

The only way I could get the return to show the right data was to use the override "Contribution deduction" field.  It leaves the FMV field on the Form 8283 blank, which is not ideal, but it populates Line 12 (gifts to charity other than cash) with the correct number.

So I guess the workaround is to use the override.

Thanks all!