P-bulb question?

[emg53]

I have bought several new catts over the last 6 months. Some had p-bulbs with sheaths. Most of these p-bulbs haven't grown or produced flowers yet. Now I know they will take their sweet time however some are starting new p-bulbs at the base of the old one. I was wondering if they start growing a new p-bulb will the old one with the sheath produce flowers or is that a signal that the older p-bulb is finished growing?