[RWP] Project Length, What Numbers Go In the field?

[Indigo]

In Project Settings, you have project length, limit playback/recording 
time to, and then there's an inscrutible field, with three sets of 
digits, like 10 colon 00 colon 000.
I can't get it to record 1 full measure and stop.
I thought the field might be measure/beats/percentage, like you get with 
the page up/down keys.
I tried the digits 1 for the first measure, 04 for 4 beats, and then I 
can't get any percentage entry that will fill out the rest of the measure.
I tried 1 then 4 then 98percent, and it doesn't work to give 1 measure.
Believe it or not, 0 then 07 then 000 comes close to providing 1 measure 
of recording time, so I don't comprehend what digits the field wants to 
see in there.
Any clues, anyone?