First thing. You need to know what the fuel pressure is. Not all fuel injected can monitor fuel pressure. I would suggest a fuel pressure gauge is more important than a code scanner.
Is there any way you can reach, or touch the actual fuel injector on all cylinders? Sometimes you can feel if one is firing, or not just by putting your finger tip on it. Holding a hose, near, or on the injector and up to your ear, you might be able to hear a difference. Same idea with a long screwdriver.
I am not saying it is impossible that the fuel injectors need cleaning, but I am sceptical.
I have a 1996 Ford Aerostar, bought new. Around 18,000 miles I had a problem with the brake light switch, and had to take it to the selling dealer for warranty replacement of the switch. The service manager tried very hard to upsell me a fuel injector cleaning, that I would of course have to pay for. The van now has 189,xxx miles on it, and has had the head gasket replaced twice, once by a Ford dealer, in Redding, California, and one by me. I do not know if the dealer cleaned the fuel injectors when the head gasket was replaced, and I only lightly brushed the exterior, and the manifold end with a very soft brush, and gasoline.
Modern engines are designed to run 100,000 miles before needing service. Another reason I am sceptical about fuel injection cleaning.
A third reason I am sceptical about fuel injector cleaning is this. One of the best solvents for cleaning engine parts is gasoline.
One of the best ways to use any solvent to clean anything is to squirt it through a nozzle at high pressure. This is why a pressure washer, with plain water works so good at cleaning your patio, or deck.
I am going to suggest one of the cleanest places in your engine is the fuel injector nozzle.