dPMR and DMR are two completely separate and different standards but many people are confused by them because of the terminology used around them. In this post I will explain the terminology and hopefully stop any further confusion. Both of them are digital standards, just like P25, NXDN, D-STAR, TETRA, TETRAPOL, OpenSky.
They both use the same vocoder, but this does not mean they are compatible, because they use different bandwidths and simply because they are different standards. It's just like comparing Russian and English. Even though they use the same parameters (the human voice), they are different languages so will not be able to talk together.
The tiers are not related between different standards. Do not try to equate tier 2 DMR to tier 2 dPMR.