Top is the exact word for him.
This is how i view it, its like with motels, wouldnt you rather make some money having the dyno get used and make some money off of it, rather than having it sit there and no one use it making 0 money off of it? Why have something sit vacant and not make money, than something being used and making money? Its either make a good deal for a few days of tuning several cars, making around 50 bucks a pop, and if you got 2 days and around 10-15 cars you know, thats 500 bucks for 10 cars right there at 50 a peice, instead of 2 days and maybe just 1 car using the dyno or using on shop projects and not making money or having it just sit vacant? Id rather make 500 extra bucks
and just let them know hey, you can use it unless we need to use it for a bit.
What woudl probally be best is see if it can be a weekend 2 day thing, just have a person come in on sunday as well and set stuff up to make some more money.