Exactly correct....except where did you get 1996 from? The RJ flying started in 1993 I thought with CMR....Actually the start of this mess was with Eastern in the early 80s....
You are correct, it did start in the 80's at Eastern with Turboprops. Mainline pilots did not want to return to turboprops and ALPA negotiated the scope relief to allow the original outsourcing, aka, Eastern Metro Express. Later, and as a result, ASA, the original DL feeder, signed a marketing agreement in the mid-80's.
Then the camel stuck his nose under the tent, further! Along came the RJ. Comair did start flying the 50's in 1993 under the code, because it fell in the "permissable seat range" in the "then" scope provisions of the Delta Pilot Working Agreement. Their scope was weak, and only required that flying above a certain seat range and gross weight be flown by pilots on their list. The Comair RJ100, 50 seater, fell way below those restrictions.
However, the DL pilots were negotiating in the mid 90's when talks broke down over pay rates and some other desired benefits. Suddenly, but not by coincidence, ASA started flying the BAE-146 in the 1996 time frame. The Delta MEC attempted to restrain Delta and ASA from flying the BAE-146 under the brand. Apparently, this aircraft, number of seats configured by design, bumped up to, but not over the "permissable aircraft" seats allowed. Their scope and the language was originally crafted for a seat allowance (86, maybe) and a gross weight. It was crafted more for Turbo props because there were no Regional Jets prior to 1993. Once legal attempts failed to restrain further delivery of the ASA BAE-146, the Delta MEC immediately requested the company back to the table, caved on some pay rate and benefit demands that caused the previous negotiation break-down, and negotiated new Scope to limit, but grandfather, the number of BAE-146's to 21 that could fly under the Delta code. A contract was quickly signed! The arrival of the BAE-146 was, without doubt, orchestrated to create the issue, and to help close out the 1996 contract. The BAE-146 went away in 1998 when the short term leases ended. Looking back, it amounted to coordinated Corporate efforts to create an issue that would bring DL Pilot compromise and closure to the 1996 contract.
Included in that same agreement,
unlimited 50 seat jets were allowed in the scope provision of that contract as "permissable aircraft." At a later date, and maybe a different contract, a limited number of RJ70's were added to the scope provision--maybe in compromise to eliminate the "allowed" and grandfathered 21 BAE-146's.