Here is the way I look at Dyno's. This is a personal opinion and that is it.

I look at dyno's as a testing and tuning device. THEY ARE NOT A PENIS ENLARGEMENT TOOL, if you make more power on one dyno then the other that does not make your penis any bigger. Numbers on paper are just numbers on paper. Numbers at the track are the real thing.

I know there are ways to "fool" the dyno and get higher numbers. People have been doing it since dynos were first invented. Here are some things that can "improve" your numbers:

Higher tire pressure (less rolling resistance)
Thinner tires (185 instead of a 275, also less rolling resistance)
Strap the car a little lose (don't really suggest this but again less rolling resistance)
Place fans directly infront of intake pipe (ram air effect)

Now with that said I will give you an example that I tell alot of my customers. Take your car to shop "A" and get dynoed and make 200whp. Go to a test track and do a timed run from 50 to 100 mph (this will take out most of the driver error and traction problems etc) Bring you car to me and dyno and make 210whp with no changes (same day and everything). Now go back to the same test track and do the same test. IS YOU CAR FASTER NOW? That is what I mean by dyno numbers are just numbers.

Now on the other hand dynos are used for tuning and your before and after runs should be on the same dyno. Most dynojets are pretty consistant with eachother. I have had a customer dyno at Z1 and then drive straight to our shop and dyno again. Peak power was within 1hp between the two dynos and they even have the 248 and we have the 224.

As for the correction factors they are just that. A formula in the software that will try to take into account the atmospheric conditions and correct the power numbers. The difference in the CF are nothing more then different numerical valves in the formula that is used. IT IS ALSO TO BE KNOWN THAT YOU CANNOT DO A BASELINE RUN IN SAE AND THE FINAL RUN IN STD TO MAKE THE NUMBERS LOOK BETTER. Also, you can go and change the CF at any time (again since it is just a mathmatical equation that the program does). If you look at the dyno charts you can see what the CF is. Most of the time it is only between 1.02 and 1.07. This means that if you car makes 200whp uncorrected then it will make 204whp with the 1.02CF and 214whp with the 1.07CF. Again though the car will go the same speed at the track. From what I have seen the humitity makes the biggest difference in the CF. We have changed the altitude from 1000ft (what we use) to 6000ft and done back to back pulls and saw no big change in power numbers.

As for the smoothness this is what the sofeware does to make a "straight line" The dyno takes speed readings from the roller and uses that in the equation to determine HP. It then uses this reading (along with mass of roller and time) to determine the HP of that point. If you change the smoothing to 0 it will draw a line from one point to the next and so on. This will make the graph look "choppy". If you change it to 5 then the program does a best fit line on the graph.