In my business there isn't any difference between flat rate and contracting. I use the per item rates to calculate the contract price.

As an example, say I have a price for pulling power to the first can or switch, add that to the switch leg and dimmer, add a can, trim, bulb task multiplied by 6 cans and I have a total price. I present it as 6 cans on a dimmer.

On larger jobs, I'll do a T&M double-check on the final price, but it's still offered as a contract.

I'm all for anything that makes it simpler for me to figure & simpler for my client to understand.

Dave