I had one do that to me but they never mentioned it until I only got 90% of my invoice and they sent me an invoice for the other 10%. I rang them and they said thats the way it was and to p1zz off if I did'nt like it - so I did. They have since come back to me with jobs but they don't take their 10% anymore for some reason. I also bet they charge the landlord 10% as well as you.