I don't understand. I know that SegWit was tested and everything and since SegWit2X is SegWit, just with bigger blocks. What are they testing exactly and why they are on Alpha, they could just take the SegWit code? can't they simply activate it as SegWit since they reached the 80% then after 6 months, they activate the 2 blocks thing?
From what I have read, Segwit uses bit 1 to signal while Segwit2x uses bit 4 and then the hardfork part, weight limit from 4 MB to 8 MB. I guess since there is a difference in implementation between Segwit and Segwit2x changes needs to be made to the existing Segwit code which has been tested and successfully activated in Litecoin while Segwit2x is being developed and would be put to first and last testing within three weeks.