Excessive septic repair cost?

My 20 yr old septic tank was backed up. A contractor placed an 8 inch riser and installed an aerator unit, and replaced the cast iron outflow pipe to the leach field. The job took most of one day, and he had to dig down to the side of the tank-- used a small backhoe. Just got a bill for over $3000 total for cast iron pipe, aerator, concrete riser, and one day labor. Seems excessive-- am I right?