I mixed the 12-15 from a 12-25 with the 17-29 from a 13-29 and it did not shift well at all at the 15-17. Any time you mix cogs next to each other in a different order, the radial timing will not be right and the shifting will suffer.

I have mixed the 11-15 from and 11-25 11 speed with the 17-27 from an 12-27 11 speed and had better results, but it's still not perfect.