I'd love to have a K64, but it's wise to focus on one design here - this will be the first run of this board at this assembly facility.
Considering the compressed timeline, dividing attention between multiple designs would not be smart, likely allowing problematic details to slip by unnoticed.
and of course - don't want that to happen!

Plus there are benefits to multiple K16s instead of a K64.  example: the modularity would make troubleshooting much easier.