Perhaps try giving them more light. Good growth but not flower can mean inadequate light. A bit like Cym's.
Most Masd. like good light, it is the heat they dislike.
I have talked with other about temperature drops & there are really only a few of the very cool growing species that need this. Most hybrids will grow happily in a warm house.
and then there are the ones that just take there sweet time
.......waiting........waiting......
Cory