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Not sure what you mean by this. I was under the impression that the 8800 is a fully in house manufacture caliber.
It is but it is in the form factor of, and designed to replace the 2500 using some inspiration from that earlier movement. It is assembled in an ETA facility (but is utilised only by Omega so can indeed be considered in house), but the lines are blurred a little since Swatch group is such a wide ranging organisation. What I was getting at is that the 8500/8900 has no direct predecessor in terms of either size or specification within the Omega stable AFAIK, that really was a clean sheet, what with twin barrels etc. The 8800 on the other hand has some things in common spiritually (and actually) with the previous 2500, but is rather more sophisticated. The finishing is much much nicer too!
This thread discusses some of the similarities between the 2500 and 8800, granted there are many differences too:
https://omegaforums.net/threads/omegas-8800-and-2500-calibers.116928/
Will you request a regulation? +10 certainly warrants one.