I agree with most of what Crimson said. On top of that it could have been an option for them in their yearly program that Ryan offers. They sell their programs with a ton of add on's. The overseeding could have been a part of it. Just discounted if they buy a bigger package. A company like Ryan will just make the profit somewhere else.
I probably would have charged about 175.00 for that.
Unfortunately most customers have no idea what it costs to run a business so they are going to with the cheaper guy.
I have a yard in northern Shawnee that takes me about 15 minutes to mow. I charge her $30.00. $35.00 is my minimum but she is an older single lady and a parishioner at my church.
One day she came out and complained a little on how much I charge. She said it only took my 15 minutes and at that rate I should be making $120 or so an hour. After I got done laughing I explained things to her. Cost of gas, insurance, taxes, repairs, employees, etc...
She seemed to get that.