tuning

Crank degrees are exactly what it says--degrees measured at the crank.

The only time "distributor degrees" comes into play is in the spec books and shop manuals, and depending on how "you think" if using a distributor machine.

It's important, thought to understand the terminology, because if you buy a distributor which someone says "is 15 degrees" that MIGHT be 30 crank degrees and is way too long.