Self-employed but caught in benefits trap: ask the expert

I’m currently on income support. I’m a skilled and trained performer and could set up as self employed and work now, but the problem I have is that I would only ever be contracted to work for an hour and a half at a time – for maybe three or four evenings a week.  I would earn too much to be able to claim income support, yet I would not work enough hours to claim working tax credit.  I have tried to explain that although I may only be contracted to work an hour and a half at a venue, I would probably be at the venue for a total of 5 hours, would be traveling for at least a couple of hours to get to and from the venue, and that’s not including all the preparation and rehearsal, yet they are adamant that I can only include actual hours worked, and suggest I get another job, or stay as I am. I don’t understand how this can work, It’s a full-time job by itself, and is what I’m trained to do.  If I was selling any other product, cars, furniture, I wouldn’t just charge for the moment I sold the product – the price would include the craftsmanship, labour etc. As a self-employed person, would I be able to break down the cost of what I was paid?  Or is there any way around this? I feel like I’m banging my head around a brick wall and would appreciate any help or advice you can give me.