Hi Shreeja,
I have clearly explained How "Char Routine" name has become popular in my previous reply. The document which you posted was made by a SCN mate but not by SAP.
"Char Routine" is extensively used in SAP BW industry. That's why we all call it as "Char Routine".
If you observe in our transformation rule types options, SAP has given us "Routine" only but not "Char Routine or Field Routine". This can be used to update Char or KF. So Why are you getting so much confused?
Regards,
Suman