It's past time that.....

It's past the time he gets a job.

It's about time he got a job.

It's about time [that something was done or something happened]
It's past time [that something was done or something happened]

Both are used to talk about something that should have happened already, but has not. The thing or event that should have happened is stated in the simple past tense. It's about time/past time that you got your hair cut (It's too long). It's about time/past time we left the house (it's burning down).

To use "about time" or "past time" about an event or action is to state an opinion.

Yeah, what everyone else said.

"It's about time" suggests that the action taken was long overdue. Basically you're saying that "you (we, I) should have done that sooner."

Same with "past time" (past the time) for an action that has been delayed too long.

"About time" can have two meanings:

(1) Long past the right time; also, (2) approximately the right time. Thus, "It's about time you went to bed" can mean either that you should have gone to bed much earlier (often stated with emphasis on the word time), or that now is the appropriate time for you to retire.

Right, sometimes it is just used in a straight-forward way, with no insinuation that something is "late." It can be use in a very literal way, e.g., telling a kid whose bedtime is 8:00 that it's "about time for bed" at 7:55.

But it is the implied (sarcastic) meaning that I think the OP was confused about.