I think talking about easier conditions for Jadeja does not make sense if you look at avg runs scored in country where both played most number of tests. Talkign about 3 or 6 innings in SA playing or not playing hardly proves any point given,
Runs per wicket in India during Jadeja's career: 30 ( One of the hardest place to bat during his career)
Run per wicket in Pakistan during IK's career: 34 ( Easiest palce to bat during IK's career )
Home grounds are outsized sample size for both as opposed other venues. It will have far more impact on over all avg than presence or absence of any other venue.
Runs per wicket in India during Jadeja's career: 30 ( One of the hardest place to bat during his career)
Run per wicket in Pakistan during IK's career: 34 ( Easiest palce to bat during IK's career )
Home grounds are outsized sample size for both as opposed other venues. It will have far more impact on over all avg than presence or absence of any other venue.