Changing from UPC to Sky but concerned.

Hello, will try to make this point brief. Have been with UPC for years, tv and broadband (no phone available in my area, with eircom for that). Have main room recordable and 2 multiroom recordable boxes too (3 in total). The other day a sky sales girl called and offered us a cheaper package for tv. Same stations, HD recordable box in main room and originally 1 extra box (multiroom) for 99 euros incl installation. Great but what about extra room - which we use. She said she can get us an extra box to us - which she 'acquires'. She then went on to order us just one recordable box and she she will get us 3 other boxes which we will just have to ask the installer to install extra. I find this all very suspicious. She will get the boxes to us before installation date apparently. I am worried that the cards that come with the boxes she is getting won't work, also that the installer won't install the extra boxes as we are not down for multiroom. She was very convincing and in the end I don't want to go from a service which I am quite happy with to something that may not work. I am not trying to get something for nothing as I have been paying for all the boxes with UPC all along, she just was convinced that this was ok to do. Apologies for long post. Any views?