For many reasons, more recipients are eligible for RSM than for LIM. 

If you mouse-click to view the Eligibility/Payment Tables and compare the income standards used for LIM and RSM, you will see that the RSM limits are much higher than the limits for LIM.  The RSM limits are actually even higher than they appear on the payment tables, when you consider that these are the limits after deductions have been applied.  In contrast, the Gross Income Ceiling Test in LIM is applied to the gross income of the AU before any deductions (except the $50 child support disregard) are applied.

Mouse-click to see the RSM/LIM Comparison Chart. Note that the eligibility requirements are less restrictive at every point for RSM than for LIM.

LIM is less restrictive than RSM in only one way.  A non-pregnant adult may receive LIM, but not RSM.  The RSM AU can only include children and pregnant women.  The LIM AU can include both parents of the children in the AU.  For this reason, eligibility for LIM should be considered before eligibility for RSM.  Although the LIM eligibility requirements are more restrictive, LIM will provide coverage to more family members.