I was at a major UK airport the other day chatting with our refueller. We got onto the subject of salaries etc and even he was surprised when he discovered that his £30k basic salary was more than I am on as a turboprop F/O - it makes you wonder when the guy fuelling the plane is earning more than the bloke flying it... I wonder if the pax realise it!
Between leaving unversity and waiting for my RAF IOT cse to start I worked as a labourer in the steelworks.
My last week's pay in the steelworks was more than my first month's pay in the RAF: however, I had potential to earn substantially more.
That is what you have: potential. The refueller is probably at max increment and can't make anymore money in that job.