To me, the often complicated question, "what does a producer do?" has a really simple answer: delivers a product. This might seem overly simple, but it's the only simple answer that covers the work of all producers. True, sometimes it's a more artistic/musical job, and sometimes it's more about getting the people and money and schedule in check, and most of the time it's both and a whole lot more. Basically, the producer is the person who is responsible for getting the record finished, that is, produced. Got it? In the indie market, I find the person's name who pays the bill most often following the word Producer in the credits.
I am happy to produce or co-produce your album. I do not charge extra for this service, as in a higher rate, but it will certainly take more hours of my time to get the job done properly. One thing you'll notice about released albums is that there is rarely a single "mistake" on the album. One producer's job is to get 100% of the project to its most presentable state.
Producing usually comes in a little on the front end, and a little on the back end. Every situation is different, so it's not really possible to put this type of thing on a grid. Let's put it this way, I'll help as much as I possibly can.