Battery condition is "normal". I have copy/pasted the information below (in Dutch only).
Pack Lot Code: 0
PCB Lot Code: 0
Resterende lading (mAh): 8485
Volledig opgeladen: Ja
Bezig met opladen: Nee
Volledige laadcapaciteit (mAh): 8495
Aantal cycli: 22
Batterij geïnstalleerd: Ja
Ampèrage (mA): 0
Voltage (mV): 12502
Does this normally imply the whole device needs to be replaced? Or might a less rigid fix suffice? I need the device for my freelance work on a daily basis.
Since the Retina model is basically irreparable if there is a battery or logic board problem the whole unit would more then likely be replaced. Only Apple would know whether it is fixable or not.
So take it in ASAP.
Your battery data are all good, Normal condition, low cycle count of 22, very good battery capacity at 8495 mAh, and the voltage is where it should be, 12.5 volts. So something is causing the battery to discharge while it is supposed to be in sleep mode. The only way to find out what is doing that is have the techs run some diagnostics. But since everything in the Retina is soldered or glued in place, it is not likely they can do any repairs. Only the battery modules can be removed and replaced but that looks good.
Have you checked the System Preferences, Energy Saver to see that it is actually set to go to sleep?
Considering how much energy the Retina display and graphics system uses it is entirely possible that a fault there could drain the battery very quickly. If it is not fully sleeping that part of the unit would end up using a lot of power. Definitely worth taking it in for diagnostics to see what is going on.
I'm not sure if it's actually (the battery draining issue) a hardware issue and laptop needs to be replaced. If you search through this forum you will see numerous people who since going to 10.8.X their battery is getting totally drained while in Sleep Mode. My 2011 Macbook Air when on 10.7.4 would only drop 10% if left in sleep mode for 2 or 3 days. Now after upgrading to 10.8.1 when left in sleep mode for 2 or 3 days it's drops 70% or more. - Hoping 10.8.2 fixes this issue.
I went to the Genius Bar a couple of days ago, and they performed a full reset of my hardware settings (kind of BIOS reset). As result of that, the Genius saw a lot more activity in Console when my Macbook went to sleep mode and back to life.
He wanted to take in my Macbook for research but I didn't agree because this means I'd have to miss it for 5 - 7 working days; in practice this would be around 3 days, but nevertheless this is no option for me because I heavily depend on this device for my freelance work.
The battery issue has anymore not occured so far, neither the flickering of my screen, but yesterday I got a sudden (and to me unknown) 'grey screen of death'; comparible with the famous blue one but only with a proper warning message.
Isaac, the genius asked to keep the unit for testing and you really should take them up on that with the problems you are having. These are not normal behavior items and need to be checked out. While you rely on the MacBook Pro for freelancing, and giving it up for a few days is a problem, it will be a bigger problem in the MBP just dies completely. If it were me, I would take it back and have the techs do their thing with it and find out what is wrong. Ask for a loaner, see if they will let you use another MBP while yours is "in the shop" for diagnosis.