My bad. That might still be an appropriate installation depending on the design as specified by the manufacturer.
A smaller coil will tend to lower the evaporator coil temperature and remove more moisture.
So if you are in an area with a high humidity and low sensible load, this might make sense.
Bottom line, I would not call it a bad installation if it was working properly with no obvious problems just because of an apparent mis-match.
The biggest concern I would look for is coil icing.

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Jim Luttrall
Mr. Inspector.net, Inc.
Allen, Texas 75002