But how do you measure that it doesn't hurt your profit? Conversion rate may go up, but if those not buying because they felt lured with a lower price, through negative mouth-to-mouth advertising, make fewer new potential customers visit your site in a few months time, profit could eventually go down.

Negative mouth to mouth because you had to go to the store to see the price options? There are two, fwiw. Lots of people pick the lifetime upgrade option.