FAR Overhaul - new 19.108-7 Competitive 8(a) and sole source 8(a) policy.

I am curious to see how the new 19.108-7 Competitive 8(a) and sole source 8(a) policy will play out:

Below competitive thresholds. To ensure fair market pricing and to prepare 8(a) participants for competition, SBA has approved certain government-wide contracts for competition amongst the 8(a) contract-holders (see 19.111-2) at any dollar value, including below the competitive thresholds. Where an acquisition is below the competitive threshold (see paragraph (a)(2) of this section), contracting officers must first try conducting the acquisition as a competitive 8(a) order using these government-wide contracts before proceeding with a sole source 8(a) award. To determine whether SBA has provided approval for a particular government-wide contract, refer to the ordering procedures for that contract.

Anyone have any insight into these so-called SBA-approved government-wide contracts? Which PSCs will they cover? Which NAICS? Would these contracts cover construction and facilities management? This seems rushed.