Thats great for you, many people feel that way and they need the simplified structure or they feel they are being cheated. Others want an opportunity to earn more for more challenging task or a reward for better production these people are better suited for split rate.
So, it is ok with you of your employer tells you he is going to pay you 30% less than what you agreed to be paid because he thinks the job he is having you do isn't worth paying you your full wage? I don't get it. Who decides what any given job is worth? The employer? That is not a place I want to be. I can see it now. " Oh yeah, by the way, I know I said I would pay you $30/hr plus bennies but we only have $20/hr work on the schedule for now, and you can forget about any benefits untill we get some $30/hr jobs again." NO THANKS! My contract says what I will pay/earn every hour for 40 plus o.t. for after hours work. It doesn't matter if he/I am running 4" rigid or 1/2" emt. By the way, union scale is only a minimum, It is not unheard of for an employer to pay extra for difficult tasks.