Bubble Trainer and SNGPT

[Comatose]

My question pertains to SNGPT and this Bubble Trainer. My understanding of the methodology is that these calculators only allow 1 caller. Thus, it would seem that they are both of limited value if the game is not heads up or 3-handed. Am I mistaken about this? Certaintly these calculators would be bad for pushing into a heavy field wouldnt they?

Thanks,
Comatose