Does not Compute to me. The 2/0 copper is ok for 200 amps in a residential panel but the meter is wrong. Is it a 200 amp meter base? and the utility installed a 125 amp meter? If it is a utility meter I might make a call to them and ask if they are installing downsized meters in residential services. Utilities use their own ampacity and demand figures to size their equipment. If it is the utility that decided to put in a 125 amp meter it might be based on their assesment that 200 amps cannot be drawn from that panel because their is just not the load.
A code compliant 200 amp panel must have a 200 amp meter and a 200 amp meter base as well or the main in the 200 amp panel should be 125 amps. Is this the only 200 amp suite panel? It could be fed from a meter stack that did not have a 200 amp socket installed?
I have offered a few thoughts but at the same time I am asking a lot of questions because I need a bit more info to give a definitive answer.