I know that
It is time (understood: for the speaker or for a group of people including the speaker) to do something.
It is time I or we did something.
do not mean the same thing: the first is a simple statement of fact, whereas the second means there is some kind of emergency.
How about these same structures when the action is to be performed by a second or third person?
Does the nuance stated above cease to exist between
It is time for you/him/her/them to do something.
It is time you/he/she/they did something.