problem dm800 dual lnb

[cardantom1]

here is my problem i have a dm800 on a motor in my living room approx 2 yr old bl72 working ok ,i have then decided to put on a dual lnb to add a new dm800 bl82 to the bedroom ,but when the dish is aligned pefectly for downstairs box it has to be moved to receive signal upstairs even on freesat,any help appreciated