Transcription and Captioning parameters

Kudos on speech-to-text!  This is a game changer in alot of ways, it even handles industry jargon and brand names better than I expected. 
Is there a way to change the parameters used to turn a transcription to captions?  The character count seems a bit low.  How does the software decide how many characters per line?  I understand I can edit after the fact, but I'd like to see a better baseline to start from.  This is with Premiere 15.0, not the Beta version.

Thanks