I hope they had BOTH a 4 element and a 6 element up at the same time to compare things as they should be.There will be a SMALL differance but not worth the effort/expense to change.If it was an initial purchase/install I would say go for it but you asked if the UPGRADE was worth it.It is human nature to find results as you would expect them,ie. expect a big increase because someone told you should therefore you will.I used to have a paticular announcer that would constantly complain about the quality of the off-air feed into the studios.There was NOTHING wrong with it.After a while I would go behind the equipment rack and just stand there a minute or two and then ask him how it sounded.He always replied that it was much better. I did the little "adjustment" trick several times before showing him what I was really doing,or not doing in this case,in front of others.He never complained about the audio feed again.My point is that unless the two things can be compared at the same time and location it becomes a subjective issue,you expect therefore you will find.Good luck on your project.