The key here is the engine when operated from the starter is an air pump, if you restrict the intake or exhaust your compression reading will be affected. The 180 psi or more being read is within the tolerance one would expect. If you use push on guage, it is hard to hold down that "chuffing" cylinder without leakage around that sparkplug hole rubber nozzle seal.
An electric motor functions in "reverse" also...if you spin the motor mechanically, electrical voltage will be seen on the electrical connections (basically the principle behind an electrical generator).