Why are leaves on new pseudobulb so long? (den-phal hybrid)

[JFeathersmith]

I bought this plant in early May; it was on the discount rack 'cause it was done blooming. The label says "Pink Mini."

I've kept it on a table in front of a south-facing window since then - it's been within a foot of the window, though I've moved it around a bit so sometimes it's been directly in front, and other times right at the edge, but it's still a bright spot. (I have a few other small dendrobiums and I've been trying to give them all time in the "best" bright spot.) I water it at least once, but usually twice, a week, and it's been getting weak fertilizer one to maybe 3 times a month.

It's been working on making two new pseudobulbs since the summer sometime, and it seems that the biggest leaves on these new pbulbs are WAY longer than the biggest leaves on the older pbulbs.

Is this a sign it wants something different? More light, maybe?

I have another den-phal hybrid that might be doing something similar, but not to the same extreme.

It seems to be really healthy, and I noticed about week ago it has started making a spike on the biggest new growth! (Photo with spike is from today, it seems to be lengthening pretty quickly!!!!!)

Photos show: my hand under the old foliage, hand under new foliage, whole plant, and spike.