From the Atlas page...
Pay Hours for work on scheduled workdays: Crewmembers are paid the greater of (1.) Pay Credits (Flight + DH + Training, etc), (2.) Calculated Rig Time (CRT), commonly known as a Trip Rig or (3.) Minimum Monthly Guarantee. CRT is calculated based on Time Away From Base at a factor of 1:4.95, which pays 4.85 pay hours for each 24 hour period away from base (24 divided by 4.95). CRT is also paid while crews are on layover or reserve in base.
So according to this if you do a 17 day trip you shouldn't ever credit less that about 80 hours in a normal month right?