Why not charge the client a premium rate and make it worth your while. Nobody likes working later than their normal schedule but within this business, unfortunately there are times where it is required to fit with the clients schedule.

"Mr. Client, my schedule requires me to start at XX o'clock in the morning which ensure I provide myself enough time to complete projects like yours during my operating hours. Since you are requesting me to start your project so late in the day and it will take Y hours to complete, I will be charging you a premium rate to complete this."

If you agree to this please sign hear and I will see you on (insert Day and time).

They are taking you away from your family and possibly office time of working on quotes, responding to emails, ordering materials for other jobs so make it worth your time to complete this one.

This is now pure profit you are making on this customer so why not take advantage of it?