Ordinary pinky purple flower heads more paniculata-shaped than maculata-shaped. Why does it have AGM?

Genus: PHLOX
Variety: MACULATA
Cultivar: ‘PRINCESS STURDZA’
Plant family: Polemoniaceae
Hardiness zone: H7(below -20C)
Height: 

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Other data

Foilage colour
Foliage season
Flower colour
Flowering season
Soil moisture
Shadiness
Hardiness

Plant ID 7561