Thanks for all the good responses so far guys.
I have been doing penal start, and it is giving me great opening indeed.
But yesterday, I have had 2 games where we fail to seal the victory, losing at 50 points and 14 points left of opponent. They just keep spamming obersedens and penals just die so quickly it became a joke.. I didn't choose KV 8 so couldn't really effectively counter.
---
Do you guys have any suggestion to close out the late game? (~level 12+)
Other ppl have already answered most of your questions here so I'll just add some points - one needs to understand the enemy unit you're going up against. Then you can counter it properly.
Generally ppl replace penal losses with Guards, but even Guards have a tough task going up against Obers. They can beat them with vet I's "Firing Positions!" ability but vet II/III+ Obers have a 'terminator' reputation for a reason. Even 7 man cons typically just bleed you horrendously vs them.
There's no simple answer, because like a lot of COH2 - it really depends on what your opponent is doing, what their composition is and what the map area is like. At lvl 12 their vehicle-inf-arty 'triangle' (combined arms) coordination will be poor, so it's easier to exploit a weaker part of the 'triangle'. However, going heavy on one part of the 'triangle' will leave you also weaker in another and vulnerable. I see this all the time where ppl spam 4 TDs out and then the other person doesn't build any armor and those schreck inf units suddenly become a very serious problem...
Using your example: you should try to screen the JP4 off with LOS blockers or just force it back with PTRS penals/AT guns/TD of your own. Letting it get free shots on your T-34 is a slow death and JP4 scales very well with vet. People rag on about the maxim being useless, but if you can get a spotter for it, then it can suppress an ober blob before they get many shots off. You know they'll come for the VP, so their approach angles will be more predictable. Esp viable around the mid ranks, where ppl do have big blobs and are easy targets for the sustained fire ability.