I don't know the answer for different resting times due to regions, altitudes or processing methods. I mostly roast African naturals. However, I noticed that rest time can be different due to roast degree. and speed.
For roast degree, I've seen it mentioned a few times here, and found it to be true, the lighter the roast, the longer the required rest. But I also found that fast roasts, especially faster in the drying stage, require more rest, while those spending more time and slower drying, can cut the rest in half. This I found by accident with a local HB'er, and it made it fun to enjoy Tchembe on day 4, while previously had to wait a week or so.