If you have extras you only sell on site you can set them up as "Invoice Items" in SETTINGS->GUEST MANAGEMENT->INVOICING.
===Different upsell items for different rooms===
Upsell items are created on property level. However, you can activate an upsell item for a rate, and the rate can be specific for a room.
Create your different upsell items.
In the rate menu go to the upsell tab and activate/deactivate the upsell you want for the room that is attached to the rate.
===Reports and Templates===