Well for those who also have the same problem, This morning out CTO figured it out since Thirdlane uses tiff2pdf the standard size is set to letter if you remove the command for letter size it makes it Auto and now will receive letter or legal. Below is a cut and paste I what he did.

path were to find the file.

/usr/local/sbin/fax2pdf.sh
Before - tiff2pdf -f -p ${FORMAT} ${FAXFILE}.tif > ${FAXFILE}.pdf
if you look at this line the -p mean papersize ${FORMAT} is at the top of the script indicating LETTER size remove the -p and the ${FORMAT} for the line and now its set to AUTO it looks something like this
P.S. don't forget to make backups of any files before you edit them Cheers.

After - tiff2pdf -f ${FAXFILE}.tif > ${FAXFILE}.pdf