It depends on whom is making the purchasing decision. If a manager or CTO is making the purchase, and all their previous purchases require elaborate proposals as well as discounting, bundling etc, than an outlier where it's a no haggle price might make them question either the application or the company supporting it. I've personally had difficulty throughout my career in getting opensource applications approved unless there's a company behind the application willing to offer enterprise class support.
No haggle sounds great, but it hasn't been all that successful. Look at the Saturn brand, before it went under. It attracted those who dislike the traditional auto sales model, but it didn't produce a dramatic change in revenue for Saturn.
What happens when you have a non-negotiable price is that your profit margin is fixed. And for some buyers, they simply hate the idea that you're getting X% no matter what. They want to get the best deal, or more importantly, what they think is the best deal.