Interception, or one house spanning 2 signs, etc., are exclusively the result of the type of house erection mathematical format one selects to do the chart. The only house system format in which only one sign is to be found in each seperate single house, is the original house system format of the Greek astrologers (and early Vedic astrologers also) known as the sign/house or "whole sign" system; on astro.com this house format can be selected from the list of choices on the drop down menu. It may be enlightening to compare the results of the same astrological chart data in whole sign format, to the results shown in other house-system formats.