I agree also with Joe. Spending 10 minutes or so on a preliminary inspection in all areas, general maintenance, diagnostics, leaks, AC work etc. helps to build rapport with the customer and allows us to see what needs to be sold. I also strongly agree that we give way too much away in comparison to our investment in what it takes deliver outstanding service.
Tablets are great. It will take time to implement, be patient and try to show your techs the value it provides in the sale at the counter and the trust that it builds with the customer.
How many are paying their techs for the inspection? I think the tech should be paid for his time regardless of whether or not you charge the customer.