Considering your plant gives you flower spike every winter is good growing already!
Yeah, it is quite normal for older lower leaves to die off first. As long as it manages to make a new leaf, and the roots remain healthy, then your plant is doing good!
I don't know if you notice it, after bloom time is over, the plant rests, then goes active again after a few weeks doing new roots then one or two new leaves. And as you said you get blooms during the cool period. They do make their bloomstalks towards late Fall when temps goes cooler, so the timing of your plants blooming is just right too. My Phals sometimes lags a bit behind, will do the blooms more towards Spring, but typically it would have started bloomstalks by late Fall, maturing all throughout winter till it blooms in Spring.
I love Phals, their blooms last very long when care is met properly. We all have varying growing environements, so it is hard to compare ones plants to others. But as long as your plant is giving you good growth, that is just quite okay!
