Macros - acceptable margin of error?

nyiballs

What is a reasonable margin of error on your macro splits?

I'm on a 50-30-20 diet, for example. If I go 54-29-17, I consider that close enough. But... Is there a number at which point to draw the line? I've been saying if I'm more than 5 points off of any macro, that's no good. But, 5 points off a 20% macro is far more significant than 5 points on a 50% macro... Do you use percent instead, ie, you can't be more than 10% off your macro (2 for a 20, 5 for a 50, etc)?