The short answer is development never stops, and we won't stop working on one platform to solely concentrate on another - while we have developed Cummins support, we've also developed support for 3 new GM controllers and added tables to a number of existing controllers.
The long answer.....
I would suggest that we will need a couple of weeks after release to settle down our 5.9L support before we move onto 6.7L.
While each platform we release support on is different, from our experience with the Duramax I can tell you that we released LB7 and LLY support (2 distinct platforms) within a few months of each other.
In terms of ongoing development, the tables available now for LB7 and LLY are 100% more than in our first release. Products evolve, the skill level of tuners evolve, after market parts evolve, and EFILive evolves with these changes. 5 years after our release, we are still adding functionality - although this is now reduced to providing tuning control for new parts.
Our first Duramax releases provided a tool never seen before in the Duramax world. The tuning in those first releases produced the same if not better results when compared against box tuner. For racers and pullers, our release provided a stable benchmark to develop suitable tuning for their specific applications. The difference was the feedback users were able to provide with the scan tool.
It was those scan tool logs over weeks and months that allowed us to diagnose conditions, and find solutions with additional tables in between developing support for new controllers. Our users won't need to provide detailed descriptions on how their truck feels, and we won't need to attempt to interpret what they say and feel - the detail will be in the data.
Like Duramax, we are highly confident that our first release will produce better results than box tuners. We also expect that over the coming months additional functionality will be added.
I expect that we will have 6.7L in beta and we will be adding tables for 5.9L at the same time based on customer requests and logs.
Cheers
Cindy