Astrology is a combination of mathematics and geometry. It has calculations, specific degrees and time. Why is it still that we have different predictions for the same planetary movement?

It is really a good question. Astrology is based on few mathematical calculations on basis of which Planets are placed in different houses of Zodiac signs.Moreover on the basis of the placement of planets, the predictions on Astrology are made.Astrology is based on very simple logics of practical applications of nature and positions of the planets required for perfect predictions.The theoretical part of Astrology actually were the concepts , realization and views of the ancient philosophers or Monks or Saints before more than thousands of years.But if we try to follow or apply the same concepts at era of twenty first century, it would not be practically justifijustified.And another most important consideration is the Experience of the Astrologer.Like any other professional subjects, an Astrologer gaining knowledge through the experience , own realisations and creative thoughts that may differ from one Astrologer to another during the analysis of same Horoscope at Astrological points of view.