I dont think it'll lose its effectiveness, but I'm by no means an expert in paraliminal technology. I wonder if the "effectiveness" loses its quality in combining mutiple paraliminals. Have you noticed any improvements since creating them? How many paraliminals are you copying the "meat" from to another tape? I'm going to start my own experiments soon once I get my tape collection on my computer and will be copying the meat from multiple paraliminals onto one tape.
I would really like to copy the meat from a whole course like Consistent Achievement onto one mega tape, but it might be counter productive.