Code doesn't lie :)  It's likely your logic is still incorrect.  Are you working with mulitple Payout__c records?  Is it possible your month is correct for one of the records, but incorrect for the last record, throwing off your nextMonth and closingMonth if checks?  Would help if you could post the rest of your class along with the test class.

Thanks James :)  I'm certainly not disputing the results, just trying to figure out how to get it covered.  Here is my entire test class so far; I'll also post my trigger and utility class next:

@isTest

public class PayrollTester {

    public static testMethod void standardTest() {
        
        //Scenario 1a - After Cha-Ching/Junior Rep/Current Structure/No Rent Spread/
        //Listing - Active (or NULL)/Not Commission-Only
        
        //Example Data
        //Insert Jeff Payroll Account
        RecordType rt = [SELECT Id FROM RecordType WHERE SObjectType = 'Account' AND Name LIKE '%Person%' LIMIT 1];
        
        Account JeffPayroll = new Account();
        
        JeffPayroll.RecordTypeId = rt.Id;
        JeffPayroll.LastName = 'Test';
        
        insert JeffPayroll;
        
        //Get Current User
        User currentUser = [SELECT Id, Senior_Solutions_Consultant__c
                            FROM User
                            WHERE ProfileId = '00ed0000000yEks'
                            AND IsActive = TRUE
                            LIMIT 1];
        
        currentUser.Senior_Solutions_Consultant__c = FALSE;
        update currentUser;
        
        //Insert Scenario 1 Opportunity
        rt = [SELECT Id FROM RecordType WHERE SObjectType = 'Opportunity' AND Name LIKE '%Home%' LIMIT 1];
        
        Opportunity Scenario1 = new Opportunity();
        
        Scenario1.RecordTypeId = rt.Id;
        Scenario1.OwnerId = currentUser.Id;
        Scenario1.AccountId = JeffPayroll.Id;
        Scenario1.Name = 'Test';
        Scenario1.StageName = 'Test';
        Scenario1.CloseDate = System.today();
        Scenario1.FMV_New__c = 1000;
        Scenario1.MPH_Rent_to_Offer__c = 1000;
        Scenario1.Cha_Ching__c = TRUE;
        Scenario1.Cha_Ching_Date_v2__c = Date.parse('11/05/2014');
        Scenario1.Actual_Commission_NEW__c = 10000;
        Scenario1.Closing_Date__c = Date.parse('03/12/2015');
        
        insert Scenario1;
        
        Opportunity Scenario1c = new Opportunity();
        
        Scenario1c.RecordTypeId = rt.Id;
        Scenario1c.OwnerId = currentUser.Id;
        Scenario1c.AccountId = JeffPayroll.Id;
        Scenario1c.Name = 'Test';
        Scenario1c.StageName = 'Test';
        Scenario1c.CloseDate = System.today();
        Scenario1c.FMV_New__c = 1000;
        Scenario1c.MPH_Rent_to_Offer__c = 1000;
        Scenario1c.Cha_Ching__c = TRUE;
        Scenario1c.Cha_Ching_Date_v2__c = Date.parse('08/05/2014');
        Scenario1c.Actual_Commission_NEW__c = 10000;
        Scenario1c.Closing_Date__c = Date.parse('03/12/2015');
        
        insert Scenario1c;
        
        //Insert Payroll St Property
        Property__c PayrollSt = new Property__c();
        
        PayrollSt.Name = '123 Payroll St';
        PayrollSt.Address_Line_1__c = '123 Payroll St';
        PayrollSt.Home_Sale_Opportunity__c = Scenario1.Id;
        
        insert PayrollSt;
        
        //Insert Active Listing
        Listing__c active = new Listing__c();
        
        active.Name = 'Test';
        active.Property__c = PayrollSt.Id;
        active.Listing_Status__c = 'Active';
        
        insert active;
        
        Scenario1.Listing__c = active.Id;
        update Scenario1;
        
        //Expected Result
        //New payout record created with a commission of: $250.00 and a payout date of: 12/15/2014
        //New payout record created with a commission of: $800.00 and a payout date of: 04/15/2015
        
        //Simulate Cha-Ching FLOW
        Payout__c juniorBonus1 = new Payout__c();
        
        juniorBonus1.OwnerId = currentUser.Id;
        juniorBonus1.Account__c = JeffPayroll.Id;
        juniorBonus1.Opportunity__c = Scenario1.Id;
        juniorBonus1.Property__c = PayrollSt.Id;
        juniorBonus1.Junior_Deal__c = TRUE;
        juniorBonus1.Junior_Bonus__c = TRUE;
        
        insert juniorBonus1;
        
        Payout__c juniorCommission1 = new Payout__c();
        
        juniorCommission1.OwnerId = currentUser.Id;
        juniorCommission1.Account__c = JeffPayroll.Id;
        juniorCommission1.Opportunity__c = Scenario1.Id;
        juniorCommission1.Property__c = PayrollSt.Id;
        juniorCommission1.Junior_Deal__c = TRUE;
        
        insert juniorCommission1;
        
        //Check Results
        juniorBonus1 = [SELECT Id, Commission_Amount__c, Payout_Date__c FROM Payout__c WHERE Id = :juniorBonus1.Id];
        juniorCommission1 = [SELECT Id, Commission_Amount__c, Payout_Date__c FROM Payout__c WHERE Id = :juniorCommission1.Id];
        
        System.assertEquals(250, juniorBonus1.Commission_Amount__c);
        System.assertEquals(Date.parse('12/15/2014'), juniorBonus1.Payout_Date__c);
        System.assertEquals(800, juniorCommission1.Commission_Amount__c);
        System.assertEquals(Date.parse('04/15/2015'), juniorCommission1.Payout_Date__c);
        
       //From here on down, I am taking stabs at trying to get those lines covered
        Scenario1.Cha_Ching_Date_v2__c = Date.parse('12/22/2014'); //The Payout object has formula fields which display this from the Opp
        Scenario1.Closing_Date__c = Date.parse('12/22/2014'); //The Payout object has formula fields which display this from the Opp
        update Scenario1;
        update juniorBonus1;
        update juniorCommission1;
        
        //Check Results
        juniorBonus1 = [SELECT Id, Payout_Date__c FROM Payout__c WHERE Id = :juniorBonus1.Id];
        juniorCommission1 = [SELECT Id, Payout_Date__c FROM Payout__c WHERE Id = :juniorCommission1.Id];
        
        System.assertEquals(Date.parse('01/15/2015'), juniorBonus1.Payout_Date__c);
        System.assertEquals(Date.parse('01/15/2015'), juniorCommission1.Payout_Date__c);
        System.assertEquals(2015, juniorBonus1.Payout_Date__c.Year());

//there will be more to write for Scenario 1b and 1c after I figure this out