The reply I got was:

"Character width is fixed in Times-Roman be its I or W , take same width where as in times new Roman it’s different

When we write more text in pdf it make lots of difference "

and:

"/.../CompuSet/Txt-PDF/Txt_PDF.sh , is used for converting compuset text file to PDF.
Txt_PDF.sh able to convert and make use of the Times-Bold/Roman font.
/.../CompuSet/perl_xml/xml_processing-1.6.pl, is used to convert XML to PDF.
xml_processing-1.6.pl able to create PDF but since font Times-Bold/Roman is NOT available, its using available font (Times-New-Roman)."

Thanks, and I'll check out prTTFont.