One-cut upgrades do date back to that era. The change from an IBM 1130 with a 6 us cycle time to a 3 us cycle time was minimal. Indeed the machine had to run

One-cut upgrades do date back to that era. The change from an IBM 1130 with a 6 us cycle time to a 3 us cycle time was minimal. Indeed the machine had to run at 3 us to drive the printer; if you never cleared the printer interrupt you got a free upgrade.