same thing I thought at first when I found out the screws were on the bottom of the carb, "BUT", I read further and found out that you don't need to put those four screws in the bottom of the car to tune it. You can leave them out and just use the two top screws while tuning and be able to pull the whole carb apart from the top until it's tuned then take them off but the four screws back in..
Also I've never had my car at a Dyno shop and never felt the need for it. It's like paying somebody to have my fun.. this is my hobby and my fun and I like to take it down to the track and take passes and make adjustments..
