How much does low-VOC paint change an interior repaint estimate?

When comparing interior repaint estimates, how much of the total usually comes down to the paint line, and how much to preparation and labor? I’d like to understand whether choosing a higher-priced low-VOC paint tends to make a noticeable difference to the overall quote, or whether materials are a smaller share once the work is included.

For a fair comparison, should each estimate name the paint line and number of coats, itemize primer and surface preparation, and price labor separately from materials? I’m also wary of treating low-VOC as meaning odor-free. What details have helped you compare estimates without assuming the cheapest paint or the lowest total is the better value?