Clear Pricing for Network Services

I had to buy some switches recently and needed to gather a second quote from another vendor. I went to the Dell website and was pleasantly surprised to quickly find a clear price and a buy-now button for each device on their website.
Normally you’d need an account of the vendors portal to get this information, so it is refreshing to have straightforward access to clear hardware pricing. However it was the list of professional services options shown in the attached image that caught my eye.
You can choose options for ‘rack and cable’ basic deployment or more comprehensive ProDeploy solution. The out-of-hours cut-over and other on-site planning options are a lot more expensive, but I’d imagine those tasks require more polished and experienced engineers to be engaged, and a lot more time-risk. Lastly you have the more tightly defined remote consulting options, with a 1-hour or a higher-priced 1-case options of the course of a single year.
You could quibble with some of the prices but I was really surprised to see fixed pricing for professional services, presented in an easy-to-consume and transparent manner.  I’ve always had an interest in business. Now that I’m more focused on network consulting I’m paying very close attention to how consulting effort is estimated and priced and delivered.
I love the idea of offering product-ized professional services. Of course there’s quite a risk with offering a fixed-price service. You need to put strong protections in place to avoid your engineers exceeding the effort you’ve priced into the offering. When it goes badly each engagement could become a loss-making opportunity.
On the other hand, offering a fixed-price for a well-defined task provides a clear incentive for process improvement. Any productivity gains you make from refining your deployment process goes straight to your profitability.
I’m going to dig deeper into this area. Do you have any experience with fixed-price or ad-hoc hourly network consulting engagements that you could share?