To me, sizing is very clear:
The Yamato Miria size is totally wrong. In fact, its size is closer to 1/72 scale:
According with the "Macross Grafitti" book, Miria has 1.71 tall in Micron size, and 8.55 mts in Meltran size (this agree with 5x factor to calculate the zentran size from Micron human: 1.71 x 5 = 8.55 mts)
According with this formula, Miria in 1/72 should measures 11.87 cms (855/72=11.87)... Exactly the size of Yamato figure!!
Also, I have the Club-M 1/72 Q-Rau kit, and it comes with a Miria figure, and its size is the same, 12 cms.
I'm in travel out of my Country, but when I arrive to my home I'll take a pic to my 1/72 stuff, including the Moscato Regult & Soldier, and Yamato Miria figure, all together.