Is the temp of your growing area the same? Sometimes being up close to a window or under lights can mean the flasks are actually a few degrees higher than the rest of your house.
Bulbos and Dends do like it warm though. If you really want to grow them as well as you can you may want to experiment with the heat mat. I've never used one, but my flasks don't grow that strongly either. Maybe a little bottom heat would do me some good. Let me know how it goes.
Thank you Royal, I will. I will be using a light, and heat mat for this upcoming batch. I'll let you know when the seeds germinate, and how the growing rates go, I may even set up a new area without a pad.