It might be less or more. Each hold should get longer as you go towards your max attempt. Meaning you should be stressing your body each time.
To be clear, each of the 4 or 5 breatholds is in itself a "max" attempt. Hold each one until you can't, then breathe up approximately double the last hold, do the next one as long as possible.
Keep doing that until they get shorter, then you'll know what your "max" is.
Mine ie: 1st hold approx 2 minutes, then breathe up 4 minutes, 2nd attempt 3:30, then breathe up 5 minutes, 3rd attempt 4:30, breathe up 5 minutes, then 4th attempt 5:45.
I know from experience that my 5th hold will not be longer, so I know that the 4th hold is my maximum.
There is a thought that breathing up for more than 5 minutes is not necessary, so you might use that rule.
Once you know your pattern, then you know the approximate amount of time needed, say to do a max attempt in a competition where there is a strict time to start your attempt.
Are you getting contractions, and if so, are you counting them?