You are over thinking this.
If you know excel then use it. Advantage to excel is you can always add columns as you see the need to break down things into separate totals.The need to refine things will happen on it's own.
You just keep track of all the money going out and all the money coming in and all the hours worked for the season/year.
From that point you will see true costs of running the business. Repairs, maintenance, line, oil, fuel for equipment, fuel truck, business ins, how much salary BF took. Profit left to buy new equipment which means ability to afford a new truck, mower. When anything wears out if it can not be replaced BF is out of business.
Sad but true I know a LCO with the 15 year old pick up, bad credit, afraid to raise his prices. Had to have his daughter co sign on for a new Toro WB that would fit in the back of his pick up bed. Yes bed, has no trailer. He's been doing this for 12 years. Still doing lawns for the $25 price he started out with most of his customers.
This is what happens when you use price to get work instead of quality.