It's different, for sure. It is used at Bristol in the bracket racing series. Just last week I had to spot a car a little over 7 seconds (sportsman, 1/4 mile), I bumped in at my leave RPM's, then dropped to an idle, leaned over and watched her leave. Looked like she drilled me, her green light on. I go back to my side of tree (7 sec spot, I got plenty of time!), bring the RPM's back up, and hammered the tree, .013, then, as I go by the tree, her red light popped on (she is -.024). Caught me by surprise, I had to look again, then I saw my win light on. It does take some getting used to.
There was also a run later on in the class where both drivers recorded -.001. I believe that the clocks count more decimals than the printer prints.
I have one of the faster cars in the class (10.60's, quickest car usually 9.90's with a couple of 10.30's/10.20's in between us), but it really doesn't matter to me one way or the other. I try to run my own race. I'm just happy to have a nice place to race 1/4 mile!

Brian


edit: In the picture, you can see her green light on, but it popped red just as I cleared the beams.