Around here, a disconnect with overcurrent protection,is required to be withing 5' of the Meter Base.
It is allowed to have the meter on the outside of the house back to back with a Panel inside of the house as long as the panel has a main breaker in it and is within 5'.
If we were to do what you were saying here,we would have to install a disconnect with overcurrent protection within 5' of the meter, which would then turn the service to the pool house into a feeder.
Now we have a disconnect on the outside of the house and one on the inside of the house. which in my mind is a violation because the disconnects to completely shut everything fed off of that one service are not grouped in one location.
In my mind , the reason for grouping the disconnects is to be able to shut down all the power provided by that service in one location at one time.
If you shut the outside disconnect off for the pool house at the meter on the house,
the house is still energized because the main is still on in the inside panel.
To me this is not grouped, and defeats the purpose.
and if you can't consider the Meter itself as a disconnecting means, I would say this installation is a violation.
They would have been money ahead to have installed a big enough panel to begin with so they could have fed the pool house from a breaker in the house panel or a combo meter main with a spare breaker and this would have not been an issue.
If the inspector indicated that a disconnect would have to be added to the outside of the house, for the house, since we added the disconnect for the poolhouse, I would have to say that he was correct if for nothing other than grouping purposes.
Although it look acceptable to extend service conductors from the load side of a meter (without a disconnect ) to a seperate structure with a disconnect by all the drawings I see posted, We are not allowed to extend the service conductors more than 5' from the meterbase. I have never seen in our area where the service conductors were extended from the load side of the meter base for very far at all.
I would call the inspector in your area and get his advise before I ever got started, if for nothing else other than to passify my decision.
all this is just my opinion for whats it's worth.
JAP.