I believe ....
That in addition to the typical 10% for most cruise lines - some enterprising TAs will form their own "group" reservations and secure an additional 1 in 16 "rebate" of cruise only fare. Plus some LUXE lines rebate at lower ratios - like 1 in 10 or 12! Also, depending on the cruise line - amenity points of varying quantity are available. These can be converted for passenger spiffs like gifts, private parties or cabin credits - but these points can sometimes be converted into a per cabin cash payout to the TA. Plus - for larger agencies - they can book significant capacity on sailings and have in effect a "private" or semi-private sailing with even more generous pricing breaks. I have made my own group arrangements and was faxed an amenity point conversion table for TAs. Plus I was on a semi-private sailing and the buzz from exec management was the deal we got on the sailing! At any rate, there are probably other "indirect" methods for compensation to TAs. If the CL ran a deal for booking a certain number of cabins to get a FREE sailng - then this is a bartered bonus. Valuable even though it is not cash.
NOt to say decent TAs are not entitled to fair or generous compensation - on the contrary I value the leg-work rendered by my TAs... and I have no qualms at their being paid properly - or generously. I've sailied over a dozen times and count these trips as among our most enjoyable "escapes".
Anyways.... this is what I think passes for TA compensation!