My opinion is there is no sense, because lenght is so short( only 11 meter if i made right conversion).
Also, you have to chance LNB+ install virtual converter as well and these cost few hundred Euros at least. Most likely if you do this change, you'll end up to have minor changes, but is it worth - it's a another question.
btw. There was some testing in Tele-Satellite mag. some time ago which might intrest you.
edited: gain of fibre LNB is a bit higher, which might help on weak transponders in case your dish is slight too small. How ever, it does not compensate under size dishes!
cheers!