If Mesh compression is turned on in model import settings on models with animations, no matter what setting, Vertex compression is not disabled. Turning off mesh compression console prints out correct values of the models.

To reproduce:
1.Open attached "MecanimMemoryUsage.zip" project
2.Open "TestScene.unity" scene
3.Enter play mode
4.Press "Print stats" button in game view
5.Observe in the console printed out object sizes

Expected result: all object sizes with animations are the same
Actual result: only the object with Mesh compression turned off is correct

Reproduced with: 5.5.4p1 5.6.0b4
Not reproduced on 5.6.0b5

The issue is fixed in 5.6.0b5.