If I were to actually look at meters for LFR healing, I'd see somewhere in the area of 40-70% overhealing most of the time. Simply put you are sticking six healers who may be capable of significantly higher throughput, and then finding at the end of the fight the person who topped the meter only did 9k HPS simply because there wasn't enough damage to heal.
Topping the healing charts in LFR is simply a matter of cooldown usage and sniping heals. Your Holy Paladin friend may be trying to heal the tank, but everytime their heal finishes casting the tank requires little to no healing cause there is an Earthshield, Riptide, Prayer of Mending, Living Seed, Renew, Regrowth, Regrowth, Lifebloomx3, Lifebloomx3, Lifebloomx3, Wild Growth, Wild Growth, Rejuvenation, Rejuvenation, Rejuvenation, Power Word: Shield, Efflorescence, and Efflorescence on the tank (cause every healer is trying to look good and knows they can always be healing the tank cause the tank takes consistent damage).
Think of it this way. LFR is tuned to require three (some fights could probably get by with two) healers, you have six. The other three are there just in case people take more damage than necessary (which is definately possible with LFR).
"In anything, if you want to go from just a beginner to a pro, you need a montage." /w TankSpot WTB Montage for Raiders.