It depends what you're trying to achieve though. SRP is perfect for someone who wants to add a little gloss and likes spending a little time every couple of months polishing their car.
If it's to correct defects then yes it is pretty much useless.
When you say the "wrong light" what kind of lighting to you mean? Direct sunlight, LED light, Halogen light, strip light, street lights, garage forecourt lights? Different light sources will show defects differently and in order to get a full correction on a car can easily take upwards of 20 to 30 hours, that would be for a full wash and decontamination (very very very important to make sure paint is free of contaminants or the machine polishing pads can pick this up and inflict damage rather than remove it) 2 or 3 stage polish and then topping it off with a last stage/step product (lsp) that is some kind of wax/coating/sealant etc.
Chris