Dend. phaleanopsis type spike initialization

[Paphluvr]

I have a nice purple NOID Dend. phalaenopsis type that has grown well for me and has put on about five new spikes in my care. It has bloomed once previously in my care, but only one spike with two flowers. My question is, two or three of the spikes matured but did not immediately produce a spike. Instead, there was a small dry nub at the top of the spike. A couple of weeks ago when watering I noticed that two spikes had started to develope from two of the canes. Is this delayed development normal? Is it initiated by shorter days or cooler nights? I haven't turned the heat on yet and a few mornings the temperature has been in the 65-67 F range.

Any enlightenment would be appreciated.