I spent several years with an email & Direct mail company and worked on several OEM programs during this time none of the OEM's mandated this but I have seen mandates that require the link to direct to the dealers OEM program website and not a 3rd party site.
You are correct with your averages. My comment was more a warning that some providers standard fees can be double the average. There is one large provided (Not DDC) that runs at 39% that I know of personally. As Craigh mentioned he has seen rates even higher.
There are many companies out there that will append your data. Most companies that offer email services can do this including GM's CSSR program run by Aspen, additionally most CRM and DMS companies can do this as well.
Had our key machine go on the fritz on month end, it would open but would not give you the correct key location. Chaos ensued.
And I'm sure we've all found ourselves hand writing contacts at month end as well because a DMS went down.
Cobalt does offer Fixed Ops digital package that can be flexed up and down via your DCC login. Any of your Cobalt support team can walk you through the package and will be happy to share references that have seen very positive results.