

Thanks makes more sense! Idk why the downvotes… Because in the case of an offset it would always be wrong and in the case of a speed change.
In the general case, with clock speed a and offset b:
- a x + b ≡ x (mod 12)
- a x + b = x + 12k
If a=1, normal speed with offset,
- b = 12k ≡ 0 (mod 12)
So it works for any multiple of 12h offset (ie no offset)
If a≠1,
- x = (12k - b)/(a-1)
It isn’t always in a day, so you can end up having to wait multiple days for it to be right
It’s not that deep