I find when pricing commercials just quote exactly what you want from the job plus 10%, if then successful you've had a result, if they think it's a little expensive you've got good room manoeuvre.
Last good size commercial we did was for a public house, the brewery wanted three quotes, we submitted ours at £675, we got the job, on the day of the job the landlord said he was pleased we got the nod but was surprised as the other quotes were £350 and £190!!
This job was two days work.