Read my articles http://navagrahastro.blogspot.in/ and you will get a better insight into astrology.
Strength here means the success factor as far as a house is concerned. Each house signifies many things which are given in detail in my articles.
The 7th house mainly signifies marriage. And a strength of 36.20% means the success factor in marriage is that much. Not a very good score. Still you will have a marriage. Do not have much expectations of a highly successful married life.
Your 4th house which also signifies success in education has 48% strength which is just above average. So it looks like your time of birth is after all correct. Your career house is just average, a pass mark is there.