Re: simplification...yes, and that's actually correct for a nonlinear axis (like the log axis), while what I did was close, but not correct.  I'll fix that.

Re: hasattr check: I personally would rather leave that in, as it signals to a projection author that this method is recommended but optional.

Re: catching everything.  I don't like it either in general, but I do think that it's the appropriate thing to do in this circumstance.  The approach is to pad the interval if at all possible, but if not, just don't pad.  Much better to potentially lose a tick on the end of the interval, then a stack trace (in case anything goes wrong in the padding).

Re: two blocks; I like the two blocks, because a floating point exception that gets raised on one end might not on the other, so we get the benefit of the padding at least on one end, in that case.