The E120 architecture was accepted as being a "subset" of the main line "interior decor". Consequently, a large autonomy was given to the future designers of Level62 about the design of their architecture and their software. The divergence between DPS4 and DPS7 took place in 1968! However, at that time, it was implied that the upper range of the line should be able to operate in the lower level "mode"; this specification was later dropped.
It was initially envisioned that the E120 decor had to be the same as the one of the PCP, so that a single engine could be used on the subsystems and on the lower end of the line. This last approach was abandoned by November 1968, at Paris request to use a minicomputer 16-bit decor instead of a variable length "main frame" decor for the PCP.
The E120 project subsisted through the GE-Honeywell merger and gave birth to the Series 60 Level 62 product line.