possibly sub-par carbonation in bottles

I have bottled a batch of coopers lager and feel something in my preperation and carbonation "thinking" messed up some of my batch. I used a mixture of regular 12oz amber bottles and some bottles that were slightly larger than 12oz. I would say the slightly larger bottles are 16 oz, and I utilized the coopers tablets for both of these varieties of bottles. (1 tablet is the RX for a 12oz)They have been bottled for 1 week and I cracked 1 of each size to sneak a peak of the process of carbonation. Obviously carbonation is less in the bigger bottles, should this effect the quality of the beer, maybee its just taking longer for conditioning the larger bottle. Guess i will use priming sugar next time then it wont matter the size of bottle I use. Just wanted some thoughts from the experienced brewers.

3 weeks at 72 deg minimum, is what is needed to properly carb a bottle. You are way too early to be testing bottles. Let them go another 3 weeks MINIMUM before you test again. After they are carbed they will still benefit from a few months of aging in the bottle.