I have noticed this. In everyday speech in India वह seems to be pronounced as 'vō'. But maybe that is just fast talking, because literally it is 'vah'. Maybe that is how a slow speaker would say it, I'm not sure.
Maybe they are easing us in, teaching us the simplest form before we become conversational. I would love to hear an expert opinion here.
This is actually covered in the tips & notes for basics 1: https://www.duolingo.com/skill/hi/Basics-1/tips-and-notes
I'm not sure what you think focus means, but these two differ in what point (focus) you're trying to make. It's exactly the same as with the 'existential' vs 'locative' constructions: exist: सवर्ग मैं परमेश्वर है। loc: परमेश्वर सवर्ग मेंं है।
The first is used to predicate (focus on) the existence of God, and by the way, he's in heaven, vs the second is used when you're focusing on the location of God and not specifically on his existence.
The phrase closest to the verb is what's in focus.
And FYI, the Hindi writing system is almost completely phonetic where each letter has its own pronunciation. And aside from a few phonological rules you can tell exactly how a word is pronounced just by how it's spelled with no ambiguity ( unlike English). Very easy alphabet to learn!