One of several things could be going on.
1) Single phase motors are often made very cheaply, and therefore can be very inefficient. Your motor could be one of these.
2) Meters have multipliers. Your old meter could of had the wrong multiplier, or your new meter could have the wrong multiplier. I worked for the local power company in their meter department quite a few years ago and they had a batch of meters come through that had the wrong multiplier. The multiplier the meter was built to did not match the multiplier on the written plate on the meter. That problem was not caught until those meters got out to the customers and they complained about their bills being too high. The power company had a portable test rig that one of their employees took out to the customers location and measured the usage and compared it to the meter and they found the customers meter to have the wrong multiplier. This is highly unlikely, but it did happen.
1) Single phase motors are often made very cheaply, and therefore can be very inefficient. Your motor could be one of these.
2) Meters have multipliers. Your old meter could of had the wrong multiplier, or your new meter could have the wrong multiplier. I worked for the local power company in their meter department quite a few years ago and they had a batch of meters come through that had the wrong multiplier. The multiplier the meter was built to did not match the multiplier on the written plate on the meter. That problem was not caught until those meters got out to the customers and they complained about their bills being too high. The power company had a portable test rig that one of their employees took out to the customers location and measured the usage and compared it to the meter and they found the customers meter to have the wrong multiplier. This is highly unlikely, but it did happen.