Maintenance man charging percentage of tool set value?

[Jourdain Francine]

My fiancée and I just bought our first duplex that is already occupied. We hired a friend who does maintenance for a large real estate management company. He has recently started doing personal jobs on the side but is new to the business part of it.

He went to a unit and replaced an outdated thermostat, fixed a light fixture that was hanging, and sprayed WD-40 into the units entrance lock because it was giving the tenants some trouble.

When we got the invoice, he charged for 45 minutes of labor but also charged an extra $30 for additional fees and had no further description. When politely asked to breakdown what made up the additional fees he said it covers mileage, any supplies he has to use and 2% of his tool set value.

I am wondering if that makes sense. Especially paying for his tool set value. I do not see anything more than a drill being needed. Shouldn’t the expense of needing to periodically replace tools be put into their hourly cost? What are others experiences with hiring out maintenance? Thanks!