Hmm ... maybe What I suggested some time ago, when the first rumours appeared about the "1. August" demo-team under transition. The 24. Division with its 70. Regiment at Yangcun is still equipped with the oldest J-8A and E-models ... so it makes more than sense to re-equip this unit too !!
I think you are right and it sorts of make sense that they are adding to the beijing military region now after already adding to shenyang, guangzhou, nanjing and Chengdu military region. Although, Beijing MR sorts of have 2 J-10 regiments now with this regiment + FTTC + the J-10s in August 1st team.
My educated guess is that they are doing testing or ferrying aircraft over long range. Correct me if I am wrong, but even F-22 have external fuel tanks for long range transit right? (I don't know why they have dummy missiles on their though)