U-verse Upgrade from u300 to u450?

Why is there an additional box charge when upgrading from u300 to u450? That seems ridiculous. Currently, if you have u300 and have 1 DVR and an additonal box at no charge.... this will change when upgrading to u450 per website.. Says customer will be billed an additional $8.00 per month for the 2nd box.... WHY??? with u300 2nd box is free so why if i upgrade you charge me for 2nd box... doesnt make sense to me.... This caused me NOT to Upgrade...