I think it definitely depends on their job or occupation. Of course Drs, Nurses, Spa attendants and entertainers are paid differently than Waiters, bartenders, stewards, cooks etc.
I spoke to a cocktail waitress from the Ukrain on our Valor cruise the first of the month. My family were all in a dispute over how many hrs they work etc. My sister did not believe they worked 12 hr days. The waitress said...oh yes we do! We have other jobs too. We asked her about the contracts. She said they have 3, 6, 9, 12 and even longer contracts for those who want them. She said they are paid in US $$ and when they convert them to their currancy they lose a lot of money unlike some other Countries where she said the US $$ is strong.
She said there are no workers on the ship from Mexico. I wonder why since the pay there is really low. While in Mazatlan we asked a hotel manager about the pay the landscapers made. He said they are paid 60 pecos a day. That is $6.00 per day! This would be a golden job for them.
When we were on the NCL Wind we were talking to a couple in their late 50s who did craft classes once a day. She said that she sent a tape to NCL telling of her interest to teach craft classes. They were offered their cabin plus dining in any of the diningrooms with full use of the ship in exchange for teaching one 1hr class daily and paying their gratuities so basically they pay $70.00 x 2 per week which is $140.00 a week and they get their room and board and the luxuries of cruising for teaching one class a day. Not too shabby!