Shashtiamsha is seen for all aspects of life like birth chart. It should be used as an independent chart and same technique for analysis should be used as for lagna chart. Parashara has given shashtiamsha chart more importance than the birth and navamsa chart. To treat Shashtiamsha as an independent chart, you should have correct birth time. Shashtiamsha lagna changes in every 2 minutes therefore birth time should be accurate.
There is a misconception that D60 chart is used see past life this is not so true. It is actually used to see the PAST LIFE KARMA and how that KARMA will manifest in this life whether is a good way or a bad way.