Always Multiply Your Estimates by π (2013)

In my head I usually do "an order of magnitude" increase to do things properly. 1h to 1d to 1w to 1M to 1Y.

Thats kind of like a multiplier of τ=2π

....that's not an order of magnitude each time

“Order of magnitude” is a colloquial, imprecise term that doesn’t actually mean “exactly ten” (otherwise, people would just say “ten”).

In an engineering context, I would interpret it to be "roughly ten times", because that is what it means. And the same argument,that if they meant something else, would just say "three", or what have you.

In this case h-d is 8x, d-w is 5x, w-m is 4x and m-y is 12x.

This is after all just unimportant pedantic, but if clear and simple communication is the goal, it probably makes more sense to describe it as the next calendar unit up.

For interest sake, it looks like non-decimal reference values have been used https://en.m.wikipedia.org/wiki/Order_of_magnitude