However, large number of assists did not improve the offensive flow. Can someone explain why?
I was told that the offensive flow is dependent on how good you team's assists / my players' assist abilities are.
Here are my games: (53015398) (49722654) (48947925) (46422811)
It sounds like you're looking at it backwards. Offensive flow is simply the handling and passing skills of your team - increasing this makes you more likely to increase the number of assists you have. But the calculation only works in that direction - if you have awful offensive flow but are playing a motion offense against a 2-3 with atrocious OD, you may rack up 30+ assists but that won't mean your flow will go up.
One thing to keep in mind is that in most offenses, passing on your big men doesn't really show up in the flow, but good passing on bigs in a look inside can lead to a lot of assisted buckets on passes from one big man to another (or to a driving guard). The best way to look at it is that the ratings displayed after the game are a nice approximation of your overall team abilities but the game at its core still looks at each individual player's skill set and the matchups matter most there.