I've played with it on my 11.2 to one 34 degree 4" stroke smallblock.....never found any conclusive results.

I've taken out from 4 to 10 degrees once I hit high gear, via my Digital 6 plus MSD box.

No real difference in ET or MPH using the switch.

I've even tried launching at like 38 degrees and taking out 4 degrees to get back to my normal 34 degrees total.....no difference on the time slip.