It would be nice to have this confirmed from other ships as well. The quoted pricing when increased was $15 and $40 - not $15 and $30. $30 would obviously be much better than $40.
There are TWO ways to confirm this. Either a guest like yourself on STANDARD fare ordering MedallionNet, or a guest on PLUS looking to upgrade from the included single device plan to the 4-device plan. They will both confirm the pricing.
Actually, a third way is someone on STANDARD fare who looks in the Princess App for purchasing MedallionNet pre-cruise will see the pricing offered.