Original sentence: A parcel tax is a form of real estate tax that,  or a land value tax, is not directly based on property value.Flat parcel taxes are very regressive because they require owners of smaller or lower valued property to pay the same total amount as owners of larger or higher valued property, which many homeowners believe to be unfair.However, a parcel tax circumvents the property tax rate limits of Proposition 13 because it does not vary according to the assessed value of the property.The parcel tax in its typical form as a flat tax is regressive:  While most parcel taxes are a fixed amount per parcel, some are based on the size of the parcel or its improvements.To be less regressive, parcel taxes should not be flat but instead be based on parcel size
Edited sentence: A parcel tax is a form of real estate tax that,  is not directly based on property value.However, a parcel tax circumvents the property tax rate limits of Proposition 13 because it is a flat tax on each parcel of real property and does not vary according to the assessed value of the property.Many homeowners believe this to be very unfair.Parcel taxes are very regressive because they typically require owners of smaller or lower valued property to pay the same total amount as owners of larger or higher valued property, including big mansions or massive commercial office buildings.The parcel tax is a regressive tax: Most parcel taxes are a fixed amount per parcel, though some are based on the size of the parcel or its improvements