Injury time

I wonder if medical center works correctly.

Yesterday i got exactly 72h injury on one of my player, no matter i have 2* medical center. Does is mean it was 74h 52m 48s in the beginning, but my 2* structure lowered it to 72h (-4%) or the medical center just doesn't work well?

What is the longest possible injury time?

In that case isn't 2% for every structure level too little? Matches are only every 24 hours, so regardless of whether I have 2% or 10%, the player will only miss 1 match.

i think the injury reduction bonus is on the lower side but lets take some time to analyze it.