I also want to say welcome to the OB! I agree that what you are experiencing with your Phals is totally normal. It varies from plant to plant, but some will put out multiple spikes at the same time, or maybe a second spike while the first one is still active, others will put out a secondary offshoot from an existing spike somewhere during the blooming period, or maybe even long after the old flowers have fallen off. Others are happy to just put out one nice spike each year.
It's all part of what makes things interesting, and I agree that your plants sound happy and you are providing great care.