I probably have the same humidity you do. It gets very dry in the cold winter months. Some hybrids are more tolerant of less than ideal conditions. I've had four Miltonias and none survived much more than a year. The hot summers certainly do a number.
There seem to be two types of blooms: one whose petals open like your fingers, bunched together, then spreading outward. That's how buds typically open. The other type is all rolled up, like an ice cream cone, and it unrolls to open. I've had problems with the latter opening, when I've purchased the plants in bud. The first flower or two open fine, and the rest stay partially rolled up.
I'm told if the ambient humidity isn't sufficient, the flowers won't open properly. I had it happen with two of the four I had, the other two being of the first type.
I'm glad yours is growing well for you, Nora! That's what the battle of the orchids is all about - finding plants that enjoy your conditions and culture, and extending those conditions so you can go other genera.