we grandfathered all existing SEATS! that's an important distinction. many of our old customers keep adding new paying seats (at the new pricing) and they only got to keep the old prices for all their existing seats + the ones they added during the 14 day promotion.
the 2 quick lessons learned that might be most relevant to you are: 1) make sure you reach out to customers + trial accounts and communicate personally with them on what's coming & 2) make sure to give them a reason to be happy & an incentive to add more paying seats (upsell opportunity)