The best change orders are the ones necessary to meet code (Civitello).
If it's on the drawing it's on the drawing. If it's in the specs, the specs take precedence over the drawings. If it's found in neither place, it will be what is standard in the industry, which is 3/4" bodies with 3/4" conduit. Not interested in boilerplate like perform to the satisfaction of the engineer. I am interested in the information upfront.
If the guy has a license and stamp on the drawing, he can draw something that does not meet code and be responsible for it. The legal contract requires delivery of a 3/4" raceway system, 3/4" with some 1 1/2" is not specified.
If the guy's drawing has no stamp and no license on it, statutes may require the PE supervision making it an illegal document and very non enforceable. Really throws the whole contract into a grey or worse area. Depending on the state, the PE supervision may be in the licensing statutes and carry criminal penalties like 6 months in jail. Seperately, look in the Public Safety statutes and you may see requirement for PE stamped drawings by use group type. The public safety statutes are a different animal from licensing, state police and attorney general enforcement, not a civil matter.
If it were me I would not be looking for an LB hanging in the air for pull point, I would go for a beam clamp and box without thinking too much about it. I would automatically go for the LB if I was turning and passing through a wall.
If you throw the guy enough regular work, I'm sure he will help you CYA. If you do a job phase 1, phase 2, phase 3 with three different low bidders and they know you will not or cannot pay for good changes, you should expect to get what you agreed to pay for.