As a point of information, my sample delay is reporting a latency and then applying a delay to get back to zero- which is why you can apply negative delays on the fly, you're not changing the reported latency, just the corrective additional delay.
As a point of curiosity- that one is going to stay free, but does anybody need a cheap (like $30) bigger latency fixer or a latency fixer that will do subsample delays? If so, how much maximum latency do you actually need to correct for? I don't think there's much of a technical limit on how much I can do, but it'll eat RAM and apply the max latency at all times (while correcting it to the desired amount) so I haven't really got radical with it with the free Sample Delay.
For those who don't have it here's the freebie that does small negative delays to fix latency-
http://www.airwindows.com/f/SampleDelay.dmg