Maybe the rumour stems from my activities.
The .26 is not ACES combat legal.
Being quite active with the combat crowd, I decided to combine MVVS parts to produce an ACES legal .25 engine. The engine reverts back to the combustion head button design, which also allows a different chamber for high nitro use. This design is abandoned by MVVS due to the higher cost.
With a little work, the combat cooling head can be made to fit as well.
So far, no word from MVVS that they will produce the engine themselves. Like Dar said, why should they? The difference is a mere .2cc!
Internally, Their .26 is a long stroke engine; whereas mine has a shorter stroke and bigger bore.