Technically speaking, all of those are Case garden tractor models including the 448 that was introduced for the 1980 model year and the 226 that was introduced for the 1984 model year. Yes, Jack Ingersoll did buy the division in late, late, late 1983 but that deal came with an agreement that Jack would continue to build these tractors for Case and badge them as Case for an undisclosed number of years.
What happened to that agreement has not been made public but these were tumultuous times for the industry with Case absorbing I/H and all those fat-cat brand loyal I/H top brass. I am convinced that it was those guys who put the death-hold on these tractors as Case branded units. After all, these are the same turkeys that sold off the profitable Cub Cadet line to MTD.
Even though the 3 digit models stayed in production until the start of 1989, the Case name was still on them until 1985 finished. Only the last three years, were badged purely as Ingersoll's but no new GT models were introduced in that period. Presumably, they were busy building prototype 4 digit models at that time.