I would tend to agree with the folks here that are basing their answer to the question on how fast the vehicle racks up mileage, and what type of driving is being done during those miles.
The Amsoil 25k OCI assumes normal (not severe) conditions, and basically an ideal driving environment. Also, the 25k would have to be done within a 1 year maximum time period to warrant a 25k OCI. Anything that deviates from the defined "ideality" would cause the oil to degrade at a faster rate, thus effectively reducing the maximum OCI the oil can handle.
So it really depends on the type of driving, the environment, the vehicle condition, and the amount of time over which the mileage is put on.