It's time colleges helped you compare apples to apples.
(The Boston Globe)
If the time is a present moment, why does the journalist use "help" in the past tense? Or is "helped" subjunctive?
My first reaction here was that this cannot be a past subjunctive, because with BE in the first or third person singular the same idiom calls for simple past WAS rather than subjunctive WERE:
It is time I was in bed.
It is time he was going.
However, a little quick Google-Booking turned up a handful of such uses as time he were and time I were down to about World War I. Moreover, a common variant of the idiom employs the modal should, which often replaces irrealis subjunctives:
It is high time this war should be ended.
So I think, Yes, this is a past subjunctive, employed to express a proposition which is not a fact (but should be). And like the past subjunctive in other cases, it has lost its distinctive forms for 1st and 3rd person singular BE:
If he was/were here he would have something to say about that.
The expression it's time can be followed by to + infinitive, for + object + to + infinitive, or subject + past tense verb.
There is no difference in meaning, other than who is being referred to -- and all 4 variations refer to present time; in #1, the referent could be the speaker or one or more listeners, depending on the context. To my ear, the subject + past tense verb construction sounds more judgmental or critical: in #3, the critical tone is directed towards the third person, a female, and in #4 reflexively towards the speaker him- or herself.