I am playing the OpenXCom. I read elsewhere about what determines whether your soldier(s) are gifted with PSI in the original X-Com (not the Open version), and from what I could tell, apparently this is partly based on luck (randomized), and partly about your soldiers rank, will etc.?

Most importantly, according to some that calculation (decision whether a certain soldier is gifted) is made at the precise moment when you put a soldier in the PSI lab. Not before that, and not after that.

This leads you to be able to e.g. savescum yourself with many PSI-capable soldiers, even all of your soldiers if you feel like it (ie. retry with each soldier as many times until they become gifted):

http://www.gamefaqs.com/boards/655782-xcom-enemy-unknown/64436720

So, does this apply also to OpenXCom, or is the algorithm possibly somehow changed in Open, or that savescumming otherwise made impossible?

Just asking... It appears to me OpenXCom has curbed savescumming somewhat e.g. during land battles, ie. you can't simply save and reload the game before the enemy turns in battles, hoping to get a more favorable outcome (to me it seems the outcome will always be exactly the same, with no variation). I guess that is fine, albeit it doesn't completely remove the ability to savescum, you just need to do it before your turn, or at least when your soldiers still have some action points.