I think the issue with conditional re-takes is that one of the driving forces of the VP system is that it is supposed to encourage the Germans to overextended and the soviets to fight forward. If you can grab once for sixteen, then abandon, knowing when you retake it'll be net 16 again...that's not much incentive to hold. And would the soviets have a chance to get their points back coming the other way, or create the inverse situation?
Maybe a compromise would be that the soviet bonus is never triggered until initiative swap, but the German bonus gets chewed away over time of occupation...for big round visualization, one point for losing it up front, and maybe another for every three weeks/month held after that. So if you say, took Urel on time, lost it in February, and reclaimed it in May, your bonus would be wiped out but it wouldn't be net negative. Of course, the soviets would still get their chance to earn +6 on history when they came back the other way...we may be over thinking this, because I can already think a few ways of gaming that system too. Probably the larger point here is that to pull up short before Rzhev/Orel/Kharkov/Stalino may keep the German player a few points safer, but it means putting yourself up for a much harder '42 and abandoning the opportunity to earn places like Kalinin and Rostov. Is purchasing a few points of safety at the cost of making points harder in '42 that bad of a thing?