Is a Salesperson Different from the Person Who Makes The Quotes?

I had an interesting discussion with my mentor lately. Some background: I promoted a team member from carpenter to operations manager. I gave a base salary plus a percentage of gross profit above a certain mark. We didn't hit that mark  so he basically just got his base salary for the quarter and was really disappointed, came in and just asked for a really high base instead.

I was talking to my mentor about how our sales flow is structured and he mentioned I need to be thinking of the sales person as a lead generator, then the person who would be managing the execution as the person who needs to put the estimates together. That kind of blew my mind a little bit but the more he talked about it, the more it made sense. 

Keep in mind our projects are all custom essentially so there's different details for everyone, even if it's kind of the same thing. If I go and make the job walk, make the estimate then sell to the team, but then try to incentivize it based on a budget, it's not necessarily fair because the production staff had no part in making that budget. BUT if I'm able to create the "at bats", the foreman walks it with the client then assigns the amount of time and material it will take. Then there's less opportunity to miss details or something get lost in communication. I can give him a plaud unit to make sure to summarize everything. This would also solve the problem of clients treating me like the project manager even though I'm not supposed to be the project manager. I was the one that shook their hand and took their deposit so why wouldn't they send me the grout selections right?

Anyway, if you read through all that - I'm curious what your opinion on this is.