Are you accounting for the fact that TurboActivate correctly detects when a user uninstalls / reinstalls an app (or even completely wipes a machine). In other words, TurboActivate (by design) detects if a customer has already used the trial and starts them off where they were before they resinstalled your app. Even if that means they get 0 days of trial.
Or to put it another way: if they use the trial then they've used the trial.
Also, TurboActivate does fraud detection. Any funny-business with date/time/timezone and TurboActivate sets the trial length to 0.
In either case, trial extensions exist: https://wyday.com/limelm/help/trials/#extensions