A lot of astrologers interpret a planet within 5 degrees of the next house cusp as in that next house, there are others that say that a planet isn't in the next house until it reaches the cusp, and there are some that consider a planet near the edge of the house (this is the "sandhi" area in Indian astrology) as having some influence in both houses. So, take your pick.
In my humble opinion, given that birth times are not always recorded accurately, and that planets usually have some latitude off the ecliptic, it makes sense to consider that a planet near a cusp may be in the next house.
